Re: [Linaro-mm-sig] [Mesa-dev] [RFC] New dma_buf -> EGLImage EGL extension - Final spec published!
So, if we wanted to extend this to support the fourcc-modifiers that we have on the kernel side for compressed/tiled/etc formats, what would be the right approach?
A new version of the existing extension or a new EGL_EXT_image_dma_buf_import2 extension, or ??
BR, -R
On Mon, Feb 25, 2013 at 6:54 AM, Tom Cooksey tom.cooksey@arm.com wrote:
Hi All,
The final spec has had enum values assigned and been published on Khronos:
http://www.khronos.org/registry/egl/extensions/EXT/EGL_EXT_image_dma_buf_imp...
Thanks to all who've provided input.
Cheers,
Tom
-----Original Message----- From: mesa-dev-bounces+tom.cooksey=arm.com@lists.freedesktop.org [mailto:mesa-dev- bounces+tom.cooksey=arm.com@lists.freedesktop.org] On Behalf Of Tom Cooksey Sent: 04 October 2012 13:10 To: mesa-dev@lists.freedesktop.org; linaro-mm-sig@lists.linaro.org; dri- devel@lists.freedesktop.org; linux-media@vger.kernel.org Subject: [Mesa-dev] [RFC] New dma_buf -> EGLImage EGL extension - New draft!
Hi All,
After receiving a fair bit of feedback (thanks!), I've updated the EGL_EXT_image_dma_buf_import spec and expanded it to resolve a number of the issues. Please find the latest draft below and let me know any additional feedback you might have, either on the lists or by private e-mail - I don't mind which.
I think the only remaining issue now is if we need a mechanism whereby an application can query which drm_fourcc.h formats EGL supports or if just failing with EGL_BAD_MATCH when the application has use one EGL doesn't support is sufficient. Any thoughts?
Cheers,
Tom
--------------------8<--------------------
Name
EXT_image_dma_buf_importName Strings
EGL_EXT_image_dma_buf_importContributors
Jesse Barker Rob Clark Tom CookseyContacts
Jesse Barker (jesse 'dot' barker 'at' linaro 'dot' org) Tom Cooksey (tom 'dot' cooksey 'at' arm 'dot' com)Status
DRAFTVersion
Version 4, October 04, 2012Number
EGL Extension ???Dependencies
EGL 1.2 is required. EGL_KHR_image_base is required. The EGL implementation must be running on a Linux kernel supporting the dma_buf buffer sharing mechanism. This extension is written against the wording of the EGL 1.2 Specification.Overview
This extension allows creating an EGLImage from a Linux dma_buf file descriptor or multiple file descriptors in the case of multi-plane YUV images.New Types
NoneNew Procedures and Functions
NoneNew Tokens
Accepted by the <target> parameter of eglCreateImageKHR: EGL_LINUX_DMA_BUF_EXT Accepted as an attribute in the <attrib_list> parameter of eglCreateImageKHR: EGL_LINUX_DRM_FOURCC_EXT EGL_DMA_BUF_PLANE0_FD_EXT EGL_DMA_BUF_PLANE0_OFFSET_EXT EGL_DMA_BUF_PLANE0_PITCH_EXT EGL_DMA_BUF_PLANE1_FD_EXT EGL_DMA_BUF_PLANE1_OFFSET_EXT EGL_DMA_BUF_PLANE1_PITCH_EXT EGL_DMA_BUF_PLANE2_FD_EXT EGL_DMA_BUF_PLANE2_OFFSET_EXT EGL_DMA_BUF_PLANE2_PITCH_EXT EGL_YUV_COLOR_SPACE_HINT_EXT EGL_SAMPLE_RANGE_HINT_EXT EGL_YUV_CHROMA_HORIZONTAL_SITING_HINT_EXT EGL_YUV_CHROMA_VERTICAL_SITING_HINT_EXT Accepted as the value for the EGL_YUV_COLOR_SPACE_HINT_EXT attribute: EGL_ITU_REC601_EXT EGL_ITU_REC709_EXT EGL_ITU_REC2020_EXT Accepted as the value for the EGL_SAMPLE_RANGE_HINT_EXT attribute: EGL_YUV_FULL_RANGE_EXT EGL_YUV_NARROW_RANGE_EXT Accepted as the value for the EGL_YUV_CHROMA_HORIZONTAL_SITING_HINT_EXT & EGL_YUV_CHROMA_VERTICAL_SITING_HINT_EXT attributes: EGL_YUV_CHROMA_SITING_0_EXT EGL_YUV_CHROMA_SITING_0_5_EXTAdditions to Chapter 2 of the EGL 1.2 Specification (EGL Operation)
Add to section 2.5.1 "EGLImage Specification" (as defined by the EGL_KHR_image_base specification), in the description of eglCreateImageKHR:"Values accepted for <target> are listed in Table aaa, below.
+-------------------------+--------------------------------------------+ | <target> | Notes | +-------------------------+--------------------------------------------+ | EGL_LINUX_DMA_BUF_EXT | Used for EGLImages imported from Linux | | | dma_buf file descriptors | +-------------------------+--------------------------------------------+ Table aaa. Legal values for eglCreateImageKHR <target> parameter ... If <target> is EGL_LINUX_DMA_BUF_EXT, <dpy> must be a valid display, <ctx> must be EGL_NO_CONTEXT, and <buffer> must be NULL, cast into the type EGLClientBuffer. The details of the image is specified by the attributes passed into eglCreateImageKHR. Required attributes and their values are as follows: * EGL_WIDTH & EGL_HEIGHT: The logical dimensions of the buffer in pixels * EGL_LINUX_DRM_FOURCC_EXT: The pixel format of the buffer, as specified by drm_fourcc.h and used as the pixel_format parameter of the drm_mode_fb_cmd2 ioctl. * EGL_DMA_BUF_PLANE0_FD_EXT: The dma_buf file descriptor of plane 0 of the image. * EGL_DMA_BUF_PLANE0_OFFSET_EXT: The offset from the start of the dma_buf of the first sample in plane 0, in bytes. * EGL_DMA_BUF_PLANE0_PITCH_EXT: The number of bytes between the start of subsequent rows of samples in plane 0. May have special meaning for non-linear formats. For images in an RGB color-space or those using a single-plane YUV format, only the first plane's file descriptor, offset & pitch should be specified. For semi-planar YUV formats, the chroma samples are stored in plane 1 and for fully planar formats, U-samples are stored in plane 1 and V-samples are stored in plane 2. Planes 1 & 2 are specified by the following attributes, which have the same meanings as defined above for plane 0: * EGL_DMA_BUF_PLANE1_FD_EXT * EGL_DMA_BUF_PLANE1_OFFSET_EXT * EGL_DMA_BUF_PLANE1_PITCH_EXT * EGL_DMA_BUF_PLANE2_FD_EXT * EGL_DMA_BUF_PLANE2_OFFSET_EXT * EGL_DMA_BUF_PLANE2_PITCH_EXT In addition to the above required attributes, the application may also provide hints as to how the data should be interpreted by the GL. If any of these hints are not specified, the GL will guess based on the pixel format passed as the EGL_LINUX_DRM_FOURCC_EXT attribute or may fall-back to some default value. Not all GLs will be able to support all combinations of these hints and are free to use whatever settings they choose to achieve the closest possible match. * EGL_YUV_COLOR_SPACE_HINT_EXT: The color-space the data is in. Only relevant for images in a YUV format, ignored when specified for an image in an RGB format. Accepted values are: EGL_ITU_REC601_EXT, EGL_ITU_REC709_EXT & EGL_ITU_REC2020_EXT. * EGL_YUV_CHROMA_HORIZONTAL_SITING_HINT_EXT & EGL_YUV_CHROMA_VERTICAL_SITING_HINT_EXT: Where chroma samples are sited relative to luma samples when the image is in a sub-sampled format. When the image is not using chroma sub-sampling, the luma and chroma samples are assumed to be co-sited. Siting is split into the vertical and horizontal and is in a fixed range. A siting of zero means the first luma sample is taken from the same position in that dimension as the chroma sample. This is best illustrated in the diagram below: (0.5, 0.5) (0.0, 0.5) (0.0, 0.0) + + + + + + + + * + * + x x x x + + + + + + + + + + + + + + + + + + + + * + * + x x x x + + + + + + + + + + + + Luma samples (+), Chroma samples (x) Chrome & Luma samples (*) Note this attribute is ignored for RGB images and non sub-sampled YUV images. Accepted values are: EGL_YUV_CHROMA_SITING_0_EXT (0.0) & EGL_YUV_CHROMA_SITING_0_5_EXT (0.5) * EGL_SAMPLE_RANGE_HINT_EXT: The numerical range of samples. Only relevant for images in a YUV format, ignored when specified for images in an RGB format. Accepted values are: EGL_YUV_FULL_RANGE_EXT (0-256) & EGL_YUV_NARROW_RANGE_EXT (16-235). If eglCreateImageKHR is successful for a EGL_LINUX_DMA_BUF_EXT target, the EGL takes ownership of the file descriptor and is responsible for closing it, which it may do at any time while the EGLDisplay is initialized." Add to the list of error conditions for eglCreateImageKHR: "* If <target> is EGL_LINUX_DMA_BUF_EXT and <buffer> is not NULL, the error EGL_BAD_PARAMETER is generated. * If <target> is EGL_LINUX_DMA_BUF_EXT, and the list of attributes is incomplete, EGL_BAD_PARAMETER is generated. * If <target> is EGL_LINUX_DMA_BUF_EXT, and the EGL_LINUX_DRM_FOURCC_EXT attribute is set to a format not supported by the EGL, EGL_BAD_MATCH is generated. * If <target> is EGL_LINUX_DMA_BUF_EXT, and the EGL_LINUX_DRM_FOURCC_EXT attribute indicates a single-plane format, EGL_BAD_ATTRIBUTE is generated if any of the EGL_DMA_BUF_PLANE1_* or EGL_DMA_BUF_PLANE2_* attributes are specified. * If <target> is EGL_LINUX_DMA_BUF_EXT and the value specified for EGL_YUV_COLOR_SPACE_HINT_EXT is not EGL_ITU_REC601_EXT, EGL_ITU_REC709_EXT or EGL_ITU_REC2020_EXT, EGL_BAD_ATTRIBUTE is generated. * If <target> is EGL_LINUX_DMA_BUF_EXT and the value specified for EGL_SAMPLE_RANGE_HINT_EXT is not EGL_YUV_FULL_RANGE_EXT or EGL_YUV_NARROW_RANGE_EXT, EGL_BAD_ATTRIBUTE is generated. * If <target> is EGL_LINUX_DMA_BUF_EXT and the value specified for EGL_YUV_CHROMA_HORIZONTAL_SITING_HINT_EXT or EGL_YUV_CHROMA_VERTICAL_SITING_HINT_EXT is not EGL_YUV_CHROMA_SITING_0_EXT or EGL_YUV_CHROMA_SITING_0_5_EXT, EGL_BAD_ATTRIBUTE is generated. * If <target> is EGL_LINUX_DMA_BUF_EXT and one or more of the values specified for a plane's pitch or offset isn't supported by EGL, EGL_BAD_ACCESS is generated. * If <target> is EGL_LINUX_DMA_BUF_EXT and eglCreateImageKHR fails, EGL does not retain ownership of the file descriptor and it is the responsibility of the application to close it."Issues
1. Should this be a KHR or EXT extension? ANSWER: EXT. Khronos EGL working group not keen on this extension as it is seen as contradicting the EGLStream direction the specification is going in. The working group recommends creating additional specs to allow an EGLStream producer/consumer connected to v4l2/DRM or any other Linux interface. 2. Should this be a generic any platform extension, or a Linux-only extension which explicitly states the handles are dma_buf fds? ANSWER: There's currently no intention to port this extension to any OS not based on the Linux kernel. Consequently, this spec can be explicitly written against Linux and the dma_buf API. 3. Does ownership of the file descriptor pass to the EGL library? ANSWER: If eglCreateImageKHR is successful, EGL assumes ownership of the file descriptors and is responsible for closing them. 4. How are the different YUV color spaces handled (BT.709/BT.601)? ANSWER: The pixel formats defined in drm_fourcc.h only specify how the data is laid out in memory. It does not define how that data should be interpreted. Added a new EGL_YUV_COLOR_SPACE_HINT_EXT attribute to allow the application to specify which color space the data is in to allow the GL to choose an appropriate set of co-efficients if it needs to convert that data to RGB for example. 5. What chroma-siting is used for sub-sampled YUV formats? ANSWER: The chroma siting is not specified by either the v4l2 or DRM APIs. This is similar to the color-space issue (4) in that the chroma siting doesn't affect how the data is stored in memory. However, the GL will need to know the siting in order to filter the image correctly. While the visual impact of getting the siting wrong is minor, provision should be made to allow an application to specify the siting if desired. Added additional EGL_YUV_CHROMA_HORIZONTAL_SITING_HINT_EXT & EGL_YUV_CHROMA_VERTICAL_SITING_HINT_EXT attributes to allow the siting to be specified using a set of pre-defined values (0 or 0.5). 6. How can an application query which formats the EGL implementation supports? PROPOSAL: Don't provide a query mechanism but instead add an error condition that EGL_BAD_MATCH is raised if the EGL implementation doesn't support that particular format. 7. Which image formats should be supported and how is format specified? Seem to be two options 1) specify a new enum in this specification and enumerate all possible formats. 2) Use an existing enum already in Linux, either v4l2_mbus_pixelcode and/or those formats listed in drm_fourcc.h? ANSWER: Go for option 2) and just use values defined in drm_fourcc.h. 8. How can AYUV images be handled? ANSWER: At least on fourcc.org and in drm_fourcc.h, there only seems to be a single AYUV format and that is a packed format, so everything, including the alpha component would be in the first plane. 9. How can you import interlaced images? ANSWER: Interlaced frames are usually stored with the top & bottom fields interleaved in a single buffer. As the fields would need to be displayed as at different times, the application would create two EGLImages from the same buffer, one for the top field and another for the bottom. Both EGLImages would set the pitch to 2x the buffer width and the second EGLImage would use a suitable offset to indicate it started on the second line of the buffer. This should work regardless of whether the data is packed in a single plane, semi-planar or multi-planar. If each interlaced field is stored in a separate buffer then it should be trivial to create two EGLImages, one for each field's buffer. 10. How are semi-planar/planar formats handled that have a different width/height for Y' and CbCr such as YUV420? ANSWER: The spec says EGL_WIDTH & EGL_HEIGHT specify the *logical* width and height of the buffer in pixels. For pixel formats with sub-sampled Chroma values, it should be trivial for the EGL implementation to calculate the width/height of the Chroma sample buffers using the logical width & height and by inspecting the pixel format passed as the EGL_LINUX_DRM_FOURCC_EXT attribute. I.e. If the pixel format says it's YUV420, the Chroma buffer's width = EGL_WIDTH/2 & height =EGL_HEIGHT/2. 11. How are Bayer formats handled? ANSWER: As of Linux 2.6.34, drm_fourcc.h does not include any Bayer formats. However, future kernel versions may add such formats in which case they would be handled in the same way as any other format. 12. Should the spec support buffers which have samples in a "narrow range"? Content sampled from older analogue sources typically don't use the full (0-256) range of the data type storing the sample and instead use a narrow (16-235) range to allow some headroom & toeroom in the signals to avoid clipping signals which overshoot slightly during processing. This is sometimes known as signals using "studio swing". ANSWER: Add a new attribute to define if the samples use a narrow 16-235 range or the full 0-256 range. 13. Specifying the color space and range seems cumbersome, why not just allow the application to specify the full YUV->RGB color conversion matrix? ANSWER: Some hardware may not be able to use an arbitrary conversion matrix and needs to select an appropriate pre-defined matrix based on the color space and the sample range. 14. How do you handle EGL implementations which have restrictions on pitch and/or offset? ANSWER: Buffers being imported using dma_buf pretty much have to be allocated by a kernel-space driver. As such, it is expected that a system integrator would make sure all devices which allocate buffers suitable for exporting make sure they use a pitch supported by all possible importers. However, it is still possible eglCreateImageKHR can fail due to an unsupported pitch. Added a new error to the list indicating this. 15. Should this specification also describe how to export an existing EGLImage as a dma_buf file descriptor? ANSWER: No. Importing and exporting buffers are two separate operations and importing an existing dma_buf fd into an EGLImage is useful functionality in itself. Agree that exporting an EGLImage as a dma_buf fd is useful, E.g. it could be used by an OpenMAX IL implementation's OMX_UseEGLImage function to give access to the buffer backing an EGLImage to video hardware. However, exporting can be split into a separate extension specification.Revision History
#4 (Tom Cooksey, October 04, 2012)
- Fixed issue numbering!
- Added issues 8 - 15.
- Promoted proposal for Issue 3 to be the answer.
- Added an additional attribute to allow an application to specify the color space as a hint which should address issue 4.
- Added an additional attribute to allow an application to specify the chroma siting as a hint which should address issue 5.
- Added an additional attribute to allow an application to specify the sample range as a hint which should address the new issue 12.
- Added language to end of error section clarifying who owns the fd passed to eglCreateImageKHR if an error is generated.
#3 (Tom Cooksey, August 16, 2012)
- Changed name from EGL_EXT_image_external and re-written language to explicitly state this for use with Linux & dma_buf.
- Added a list of issues, including some still open ones.
#2 (Jesse Barker, May 30, 2012)
- Revision to split eglCreateImageKHR functionality from export Functionality.
- Update definition of EGLNativeBufferType to be a struct containing a list of handles to support multi-buffer/multi-planar formats.
#1 (Jesse Barker, March 20, 2012)
- Initial draft.
mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
On Thu, 16 Jun 2016 10:40:51 -0400 Rob Clark robdclark@gmail.com wrote:
So, if we wanted to extend this to support the fourcc-modifiers that we have on the kernel side for compressed/tiled/etc formats, what would be the right approach?
A new version of the existing extension or a new EGL_EXT_image_dma_buf_import2 extension, or ??
Hi Rob,
there are actually several things it might be nice to add:
- a fourth plane, to match what DRM AddFB2 supports
- the 64-bit fb modifiers
- queries for which pixel formats are supported by EGL, so a display server can tell the applications that before the application goes and tries with a random bunch of them, shooting in the dark
- queries for which modifiers are supported for each pixel format, ditto
I discussed these with Emil in the past, and it seems an appropriate approach might be the following.
Adding the 4th plane can be done as revising the existing EGL_EXT_image_dma_buf_import extension. The plane count is tied to pixel formats (and modifiers?), so the user does not need to know specifically whether the EGL implementation could handle a 4th plane or not. It is implied by the pixel format.
Adding the fb modifiers needs to be a new extension, so that users can tell if they are supported or not. This is to avoid the following false failure: if user assumes modifiers are always supported, it will (may?) provide zero modifiers explicitly. If EGL implementation does not handle modifiers this would be rejected as unrecognized attributes, while if the zero modifiers were not given explicitly, everything would just work.
The queries obviously(?) need a new extension. It might make sense to bundle both modifier support and the queries in the same new extension.
We have some rough old WIP code at https://git.collabora.com/cgit/user/lfrb/mesa.git/log/?h=T1410-modifiers https://git.collabora.com/cgit/user/lfrb/egl-specs.git/log/?h=T1410
On Mon, Feb 25, 2013 at 6:54 AM, Tom Cooksey tom.cooksey@arm.com wrote:
Hi All,
The final spec has had enum values assigned and been published on Khronos:
http://www.khronos.org/registry/egl/extensions/EXT/EGL_EXT_image_dma_buf_imp...
Thanks to all who've provided input.
May I also pull your attention to a detail with the existing spec and Mesa behaviour I am asking about in https://lists.freedesktop.org/archives/mesa-dev/2016-June/120249.html "What is EGL_EXT_image_dma_buf_import image orientation as a GL texture?" Doing a dmabuf import seems to imply an y-flip AFAICT.
Thanks, pq
On Fri, Jun 17, 2016 at 3:59 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
On Thu, 16 Jun 2016 10:40:51 -0400 Rob Clark robdclark@gmail.com wrote:
So, if we wanted to extend this to support the fourcc-modifiers that we have on the kernel side for compressed/tiled/etc formats, what would be the right approach?
A new version of the existing extension or a new EGL_EXT_image_dma_buf_import2 extension, or ??
Hi Rob,
there are actually several things it might be nice to add:
a fourth plane, to match what DRM AddFB2 supports
the 64-bit fb modifiers
queries for which pixel formats are supported by EGL, so a display server can tell the applications that before the application goes and tries with a random bunch of them, shooting in the dark
queries for which modifiers are supported for each pixel format, ditto
I discussed these with Emil in the past, and it seems an appropriate approach might be the following.
Adding the 4th plane can be done as revising the existing EGL_EXT_image_dma_buf_import extension. The plane count is tied to pixel formats (and modifiers?), so the user does not need to know specifically whether the EGL implementation could handle a 4th plane or not. It is implied by the pixel format.
Adding the fb modifiers needs to be a new extension, so that users can tell if they are supported or not. This is to avoid the following false failure: if user assumes modifiers are always supported, it will (may?) provide zero modifiers explicitly. If EGL implementation does not handle modifiers this would be rejected as unrecognized attributes, while if the zero modifiers were not given explicitly, everything would just work.
hmm, if we design it as "not passing modifier" == "zero modifier", and "never explicitly pass a zero modifier" then modifiers could be added without a new extension. Although I agree that queries would need a new extension.. so perhaps not worth being clever.
The queries obviously(?) need a new extension. It might make sense to bundle both modifier support and the queries in the same new extension.
We have some rough old WIP code at https://git.collabora.com/cgit/user/lfrb/mesa.git/log/?h=T1410-modifiers https://git.collabora.com/cgit/user/lfrb/egl-specs.git/log/?h=T1410
On Mon, Feb 25, 2013 at 6:54 AM, Tom Cooksey tom.cooksey@arm.com wrote:
Hi All,
The final spec has had enum values assigned and been published on Khronos:
http://www.khronos.org/registry/egl/extensions/EXT/EGL_EXT_image_dma_buf_imp...
Thanks to all who've provided input.
May I also pull your attention to a detail with the existing spec and Mesa behaviour I am asking about in https://lists.freedesktop.org/archives/mesa-dev/2016-June/120249.html "What is EGL_EXT_image_dma_buf_import image orientation as a GL texture?" Doing a dmabuf import seems to imply an y-flip AFAICT.
I would have expected that *any* egl external image (dma-buf or otherwise) should have native orientation rather than gl orientation. It's somewhat useless otherwise.
I didn't read it carefully yet (would need caffeine first ;-)) but EGL_KHR_image_base does say "This extension defines a new EGL resource type that is suitable for sharing 2D arrays of image data between client APIs" which to me implies native orientation. So that just sounds like a mesa bug somehow?
Do you just get that w/ i965? I know some linaro folks have been using this extension to import buffers from video decoder with freedreno/gallium and no one mentioned the video being upside down.
BR, -R
Thanks, pq
On Fri, 17 Jun 2016 08:26:04 -0400 Rob Clark robdclark@gmail.com wrote:
On Fri, Jun 17, 2016 at 3:59 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
On Thu, 16 Jun 2016 10:40:51 -0400 Rob Clark robdclark@gmail.com wrote:
So, if we wanted to extend this to support the fourcc-modifiers that we have on the kernel side for compressed/tiled/etc formats, what would be the right approach?
A new version of the existing extension or a new EGL_EXT_image_dma_buf_import2 extension, or ??
Hi Rob,
there are actually several things it might be nice to add:
a fourth plane, to match what DRM AddFB2 supports
the 64-bit fb modifiers
queries for which pixel formats are supported by EGL, so a display server can tell the applications that before the application goes and tries with a random bunch of them, shooting in the dark
queries for which modifiers are supported for each pixel format, ditto
I discussed these with Emil in the past, and it seems an appropriate approach might be the following.
Adding the 4th plane can be done as revising the existing EGL_EXT_image_dma_buf_import extension. The plane count is tied to pixel formats (and modifiers?), so the user does not need to know specifically whether the EGL implementation could handle a 4th plane or not. It is implied by the pixel format.
Adding the fb modifiers needs to be a new extension, so that users can tell if they are supported or not. This is to avoid the following false failure: if user assumes modifiers are always supported, it will (may?) provide zero modifiers explicitly. If EGL implementation does not handle modifiers this would be rejected as unrecognized attributes, while if the zero modifiers were not given explicitly, everything would just work.
hmm, if we design it as "not passing modifier" == "zero modifier", and "never explicitly pass a zero modifier" then modifiers could be added without a new extension. Although I agree that queries would need a new extension.. so perhaps not worth being clever.
Indeed.
The queries obviously(?) need a new extension. It might make sense to bundle both modifier support and the queries in the same new extension.
We have some rough old WIP code at https://git.collabora.com/cgit/user/lfrb/mesa.git/log/?h=T1410-modifiers https://git.collabora.com/cgit/user/lfrb/egl-specs.git/log/?h=T1410
On Mon, Feb 25, 2013 at 6:54 AM, Tom Cooksey tom.cooksey@arm.com wrote:
Hi All,
The final spec has had enum values assigned and been published on Khronos:
http://www.khronos.org/registry/egl/extensions/EXT/EGL_EXT_image_dma_buf_imp...
Thanks to all who've provided input.
May I also pull your attention to a detail with the existing spec and Mesa behaviour I am asking about in https://lists.freedesktop.org/archives/mesa-dev/2016-June/120249.html "What is EGL_EXT_image_dma_buf_import image orientation as a GL texture?" Doing a dmabuf import seems to imply an y-flip AFAICT.
I would have expected that *any* egl external image (dma-buf or otherwise) should have native orientation rather than gl orientation. It's somewhat useless otherwise.
In that case importing dmabuf works differently than importing a wl_buffer (wl_drm), because for the latter, the y-invert flag is returned such that the orientation will match GL. And the direct scanout path goes through GBM since you have to import a wl_buffer, and I haven't looked what GBM does wrt. y-flip if anything.
I didn't read it carefully yet (would need caffeine first ;-)) but EGL_KHR_image_base does say "This extension defines a new EGL resource type that is suitable for sharing 2D arrays of image data between client APIs" which to me implies native orientation. So that just sounds like a mesa bug somehow?
That specific sentence implies nothing about orientation to me. Furthermore, the paragraph continues:
"Although the intended purpose is sharing 2D image data, the underlying interface makes no assumptions about the format or purpose of the resource being shared, leaving those decisions to the application and associated client APIs."
Might "format" include orientation?
How does "native orientation" connect with "GL texture coordinates"? The latter have explicitly defined orientation and origin. For use in GL, the right way up image is having the origin in the bottom-left corner. An image right way up is an image right way up, regardless which corner is the origin. The problem comes when you start using coordinates.
Do you just get that w/ i965? I know some linaro folks have been using this extension to import buffers from video decoder with freedreno/gallium and no one mentioned the video being upside down.
Intel, yes, but since this happens *only* for the GL import path and direct scanout is fine without y-flipping, I bet people just flipped y and did not think twice, if there even was a problem. I just have a habit of asking "why". ;-)
After all, using GL with windows and FBOs and stuff you very often find yourself upside down, and I suspect people have got the habit of just flipping it if it does not look right the first time. See e.g. the row-order of data going into glTexImage2D...
If the answer is "oops, well, dmabuf import is semantically y-flipping when it should not, but we cannot fix it because that would break everyone", I would be happy with that. I just want confirmation before flipping the flip flag. :-)
Thanks, pq
On Fri, Jun 17, 2016 at 9:31 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
On Fri, 17 Jun 2016 08:26:04 -0400 Rob Clark robdclark@gmail.com wrote:
On Fri, Jun 17, 2016 at 3:59 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
On Thu, 16 Jun 2016 10:40:51 -0400 Rob Clark robdclark@gmail.com wrote:
So, if we wanted to extend this to support the fourcc-modifiers that we have on the kernel side for compressed/tiled/etc formats, what would be the right approach?
A new version of the existing extension or a new EGL_EXT_image_dma_buf_import2 extension, or ??
Hi Rob,
there are actually several things it might be nice to add:
a fourth plane, to match what DRM AddFB2 supports
the 64-bit fb modifiers
queries for which pixel formats are supported by EGL, so a display server can tell the applications that before the application goes and tries with a random bunch of them, shooting in the dark
queries for which modifiers are supported for each pixel format, ditto
I discussed these with Emil in the past, and it seems an appropriate approach might be the following.
Adding the 4th plane can be done as revising the existing EGL_EXT_image_dma_buf_import extension. The plane count is tied to pixel formats (and modifiers?), so the user does not need to know specifically whether the EGL implementation could handle a 4th plane or not. It is implied by the pixel format.
Adding the fb modifiers needs to be a new extension, so that users can tell if they are supported or not. This is to avoid the following false failure: if user assumes modifiers are always supported, it will (may?) provide zero modifiers explicitly. If EGL implementation does not handle modifiers this would be rejected as unrecognized attributes, while if the zero modifiers were not given explicitly, everything would just work.
hmm, if we design it as "not passing modifier" == "zero modifier", and "never explicitly pass a zero modifier" then modifiers could be added without a new extension. Although I agree that queries would need a new extension.. so perhaps not worth being clever.
Indeed.
The queries obviously(?) need a new extension. It might make sense to bundle both modifier support and the queries in the same new extension.
We have some rough old WIP code at https://git.collabora.com/cgit/user/lfrb/mesa.git/log/?h=T1410-modifiers https://git.collabora.com/cgit/user/lfrb/egl-specs.git/log/?h=T1410
On Mon, Feb 25, 2013 at 6:54 AM, Tom Cooksey tom.cooksey@arm.com wrote:
Hi All,
The final spec has had enum values assigned and been published on Khronos:
http://www.khronos.org/registry/egl/extensions/EXT/EGL_EXT_image_dma_buf_imp...
Thanks to all who've provided input.
May I also pull your attention to a detail with the existing spec and Mesa behaviour I am asking about in https://lists.freedesktop.org/archives/mesa-dev/2016-June/120249.html "What is EGL_EXT_image_dma_buf_import image orientation as a GL texture?" Doing a dmabuf import seems to imply an y-flip AFAICT.
I would have expected that *any* egl external image (dma-buf or otherwise) should have native orientation rather than gl orientation. It's somewhat useless otherwise.
In that case importing dmabuf works differently than importing a wl_buffer (wl_drm), because for the latter, the y-invert flag is returned such that the orientation will match GL. And the direct scanout path goes through GBM since you have to import a wl_buffer, and I haven't looked what GBM does wrt. y-flip if anything.
I didn't read it carefully yet (would need caffeine first ;-)) but EGL_KHR_image_base does say "This extension defines a new EGL resource type that is suitable for sharing 2D arrays of image data between client APIs" which to me implies native orientation. So that just sounds like a mesa bug somehow?
That specific sentence implies nothing about orientation to me. Furthermore, the paragraph continues:
"Although the intended purpose is sharing 2D image data, the underlying interface makes no assumptions about the format or purpose of the resource being shared, leaving those decisions to the application and associated client APIs."Might "format" include orientation?
How does "native orientation" connect with "GL texture coordinates"? The latter have explicitly defined orientation and origin. For use in GL, the right way up image is having the origin in the bottom-left corner. An image right way up is an image right way up, regardless which corner is the origin. The problem comes when you start using coordinates.
Do you just get that w/ i965? I know some linaro folks have been using this extension to import buffers from video decoder with freedreno/gallium and no one mentioned the video being upside down.
Intel, yes, but since this happens *only* for the GL import path and direct scanout is fine without y-flipping, I bet people just flipped y and did not think twice, if there even was a problem. I just have a habit of asking "why". ;-)
well, if possible, try with one of the gallium drivers?
I'm honestly not 100% sure what it is supposed to be according to the spec, but I do know some of the linaro folks were doing v4l2dec -> glimagesink with dmabuf with both mali (I think some ST platform?) and freedreno (snapdragon db410c), and no one complained to me that the video was upside down for one or the other. So I guess at least gallium and mali are doing the same thing. No idea if that is the same thing that i965 does.
BR, -R
After all, using GL with windows and FBOs and stuff you very often find yourself upside down, and I suspect people have got the habit of just flipping it if it does not look right the first time. See e.g. the row-order of data going into glTexImage2D...
If the answer is "oops, well, dmabuf import is semantically y-flipping when it should not, but we cannot fix it because that would break everyone", I would be happy with that. I just want confirmation before flipping the flip flag. :-)
Thanks, pq
On Fri, 17 Jun 2016 11:44:34 -0400 Rob Clark robdclark@gmail.com wrote:
On Fri, Jun 17, 2016 at 9:31 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
On Fri, 17 Jun 2016 08:26:04 -0400 Rob Clark robdclark@gmail.com wrote:
On Fri, Jun 17, 2016 at 3:59 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
On Thu, 16 Jun 2016 10:40:51 -0400 Rob Clark robdclark@gmail.com wrote:
On Mon, Feb 25, 2013 at 6:54 AM, Tom Cooksey tom.cooksey@arm.com wrote:
Hi All,
The final spec has had enum values assigned and been published on Khronos:
http://www.khronos.org/registry/egl/extensions/EXT/EGL_EXT_image_dma_buf_imp...
Thanks to all who've provided input.
May I also pull your attention to a detail with the existing spec and Mesa behaviour I am asking about in https://lists.freedesktop.org/archives/mesa-dev/2016-June/120249.html "What is EGL_EXT_image_dma_buf_import image orientation as a GL texture?" Doing a dmabuf import seems to imply an y-flip AFAICT.
I would have expected that *any* egl external image (dma-buf or otherwise) should have native orientation rather than gl orientation. It's somewhat useless otherwise.
In that case importing dmabuf works differently than importing a wl_buffer (wl_drm), because for the latter, the y-invert flag is returned such that the orientation will match GL. And the direct scanout path goes through GBM since you have to import a wl_buffer, and I haven't looked what GBM does wrt. y-flip if anything.
I didn't read it carefully yet (would need caffeine first ;-)) but EGL_KHR_image_base does say "This extension defines a new EGL resource type that is suitable for sharing 2D arrays of image data between client APIs" which to me implies native orientation. So that just sounds like a mesa bug somehow?
That specific sentence implies nothing about orientation to me. Furthermore, the paragraph continues:
"Although the intended purpose is sharing 2D image data, the underlying interface makes no assumptions about the format or purpose of the resource being shared, leaving those decisions to the application and associated client APIs."Might "format" include orientation?
How does "native orientation" connect with "GL texture coordinates"? The latter have explicitly defined orientation and origin. For use in GL, the right way up image is having the origin in the bottom-left corner. An image right way up is an image right way up, regardless which corner is the origin. The problem comes when you start using coordinates.
Do you just get that w/ i965? I know some linaro folks have been using this extension to import buffers from video decoder with freedreno/gallium and no one mentioned the video being upside down.
Intel, yes, but since this happens *only* for the GL import path and direct scanout is fine without y-flipping, I bet people just flipped y and did not think twice, if there even was a problem. I just have a habit of asking "why". ;-)
well, if possible, try with one of the gallium drivers?
A good idea, I just need to do it at home with nouveau... which means I probably won't be getting there any time soon.
I'm honestly not 100% sure what it is supposed to be according to the spec, but I do know some of the linaro folks were doing v4l2dec -> glimagesink with dmabuf with both mali (I think some ST platform?) and freedreno (snapdragon db410c), and no one complained to me that the video was upside down for one or the other. So I guess at least gallium and mali are doing the same thing. No idea if that is the same thing that i965 does.
Thanks, pq
BR, -R
After all, using GL with windows and FBOs and stuff you very often find yourself upside down, and I suspect people have got the habit of just flipping it if it does not look right the first time. See e.g. the row-order of data going into glTexImage2D...
If the answer is "oops, well, dmabuf import is semantically y-flipping when it should not, but we cannot fix it because that would break everyone", I would be happy with that. I just want confirmation before flipping the flip flag. :-)
Thanks, pq
On Fri, 17 Jun 2016 11:44:34 -0400 Rob Clark robdclark@gmail.com wrote:
On Fri, Jun 17, 2016 at 9:31 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
On Fri, 17 Jun 2016 08:26:04 -0400 Rob Clark robdclark@gmail.com wrote:
On Fri, Jun 17, 2016 at 3:59 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
On Thu, 16 Jun 2016 10:40:51 -0400 Rob Clark robdclark@gmail.com wrote:
So, if we wanted to extend this to support the fourcc-modifiers that we have on the kernel side for compressed/tiled/etc formats, what would be the right approach?
A new version of the existing extension or a new EGL_EXT_image_dma_buf_import2 extension, or ??
Hi Rob,
there are actually several things it might be nice to add:
a fourth plane, to match what DRM AddFB2 supports
the 64-bit fb modifiers
queries for which pixel formats are supported by EGL, so a display server can tell the applications that before the application goes and tries with a random bunch of them, shooting in the dark
queries for which modifiers are supported for each pixel format, ditto
I discussed these with Emil in the past, and it seems an appropriate approach might be the following.
Adding the 4th plane can be done as revising the existing EGL_EXT_image_dma_buf_import extension. The plane count is tied to pixel formats (and modifiers?), so the user does not need to know specifically whether the EGL implementation could handle a 4th plane or not. It is implied by the pixel format.
Adding the fb modifiers needs to be a new extension, so that users can tell if they are supported or not. This is to avoid the following false failure: if user assumes modifiers are always supported, it will (may?) provide zero modifiers explicitly. If EGL implementation does not handle modifiers this would be rejected as unrecognized attributes, while if the zero modifiers were not given explicitly, everything would just work.
hmm, if we design it as "not passing modifier" == "zero modifier", and "never explicitly pass a zero modifier" then modifiers could be added without a new extension. Although I agree that queries would need a new extension.. so perhaps not worth being clever.
Indeed.
The queries obviously(?) need a new extension. It might make sense to bundle both modifier support and the queries in the same new extension.
We have some rough old WIP code at https://git.collabora.com/cgit/user/lfrb/mesa.git/log/?h=T1410-modifiers https://git.collabora.com/cgit/user/lfrb/egl-specs.git/log/?h=T1410
On Mon, Feb 25, 2013 at 6:54 AM, Tom Cooksey tom.cooksey@arm.com wrote:
Hi All,
The final spec has had enum values assigned and been published on Khronos:
http://www.khronos.org/registry/egl/extensions/EXT/EGL_EXT_image_dma_buf_imp...
Thanks to all who've provided input.
May I also pull your attention to a detail with the existing spec and Mesa behaviour I am asking about in https://lists.freedesktop.org/archives/mesa-dev/2016-June/120249.html "What is EGL_EXT_image_dma_buf_import image orientation as a GL texture?" Doing a dmabuf import seems to imply an y-flip AFAICT.
I would have expected that *any* egl external image (dma-buf or otherwise) should have native orientation rather than gl orientation. It's somewhat useless otherwise.
In that case importing dmabuf works differently than importing a wl_buffer (wl_drm), because for the latter, the y-invert flag is returned such that the orientation will match GL. And the direct scanout path goes through GBM since you have to import a wl_buffer, and I haven't looked what GBM does wrt. y-flip if anything.
I didn't read it carefully yet (would need caffeine first ;-)) but EGL_KHR_image_base does say "This extension defines a new EGL resource type that is suitable for sharing 2D arrays of image data between client APIs" which to me implies native orientation. So that just sounds like a mesa bug somehow?
That specific sentence implies nothing about orientation to me. Furthermore, the paragraph continues:
"Although the intended purpose is sharing 2D image data, the underlying interface makes no assumptions about the format or purpose of the resource being shared, leaving those decisions to the application and associated client APIs."Might "format" include orientation?
How does "native orientation" connect with "GL texture coordinates"? The latter have explicitly defined orientation and origin. For use in GL, the right way up image is having the origin in the bottom-left corner. An image right way up is an image right way up, regardless which corner is the origin. The problem comes when you start using coordinates.
Do you just get that w/ i965? I know some linaro folks have been using this extension to import buffers from video decoder with freedreno/gallium and no one mentioned the video being upside down.
Intel, yes, but since this happens *only* for the GL import path and direct scanout is fine without y-flipping, I bet people just flipped y and did not think twice, if there even was a problem. I just have a habit of asking "why". ;-)
well, if possible, try with one of the gallium drivers?
I'm honestly not 100% sure what it is supposed to be according to the spec, but I do know some of the linaro folks were doing v4l2dec -> glimagesink with dmabuf with both mali (I think some ST platform?) and freedreno (snapdragon db410c), and no one complained to me that the video was upside down for one or the other. So I guess at least gallium and mali are doing the same thing. No idea if that is the same thing that i965 does.
Hi,
Quentin did some tests for me, and the results are... not what I would have expected: https://phabricator.freedesktop.org/T7475#88454
RadeonSI works like Intel, but Nouveau does the opposite. I think the Nouveau way is correct by the spec, which makes everyone else (intel, radeonsi, weston-simple-dmabuf-v4l) get it wrong. Unfortunately, two wrongs make a right, so when weston-simple-dmabuf-v4l hardcodes Y_INVERT as set, it'll come out the right way on intel and radeon.
And it is wrong for weston-simple-dmabuf-v4l to set Y_INVERT, that I believe is clear. It is only there because of the "oops, it's upside-down" syndrome, AFAIK.
After all, using GL with windows and FBOs and stuff you very often find yourself upside down, and I suspect people have got the habit of just flipping it if it does not look right the first time. See e.g. the row-order of data going into glTexImage2D...
If the answer is "oops, well, dmabuf import is semantically y-flipping when it should not, but we cannot fix it because that would break everyone", I would be happy with that. I just want confirmation before flipping the flip flag. :-)
So many bugs that accidentally counter each other...
Thanks, pq
On Mon, Jun 20, 2016 at 8:37 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
On Fri, 17 Jun 2016 11:44:34 -0400 Rob Clark robdclark@gmail.com wrote:
On Fri, Jun 17, 2016 at 9:31 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
On Fri, 17 Jun 2016 08:26:04 -0400 Rob Clark robdclark@gmail.com wrote:
On Fri, Jun 17, 2016 at 3:59 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
On Thu, 16 Jun 2016 10:40:51 -0400 Rob Clark robdclark@gmail.com wrote:
So, if we wanted to extend this to support the fourcc-modifiers that we have on the kernel side for compressed/tiled/etc formats, what would be the right approach?
A new version of the existing extension or a new EGL_EXT_image_dma_buf_import2 extension, or ??
Hi Rob,
there are actually several things it might be nice to add:
a fourth plane, to match what DRM AddFB2 supports
the 64-bit fb modifiers
queries for which pixel formats are supported by EGL, so a display server can tell the applications that before the application goes and tries with a random bunch of them, shooting in the dark
queries for which modifiers are supported for each pixel format, ditto
I discussed these with Emil in the past, and it seems an appropriate approach might be the following.
Adding the 4th plane can be done as revising the existing EGL_EXT_image_dma_buf_import extension. The plane count is tied to pixel formats (and modifiers?), so the user does not need to know specifically whether the EGL implementation could handle a 4th plane or not. It is implied by the pixel format.
Adding the fb modifiers needs to be a new extension, so that users can tell if they are supported or not. This is to avoid the following false failure: if user assumes modifiers are always supported, it will (may?) provide zero modifiers explicitly. If EGL implementation does not handle modifiers this would be rejected as unrecognized attributes, while if the zero modifiers were not given explicitly, everything would just work.
hmm, if we design it as "not passing modifier" == "zero modifier", and "never explicitly pass a zero modifier" then modifiers could be added without a new extension. Although I agree that queries would need a new extension.. so perhaps not worth being clever.
Indeed.
The queries obviously(?) need a new extension. It might make sense to bundle both modifier support and the queries in the same new extension.
We have some rough old WIP code at https://git.collabora.com/cgit/user/lfrb/mesa.git/log/?h=T1410-modifiers https://git.collabora.com/cgit/user/lfrb/egl-specs.git/log/?h=T1410
On Mon, Feb 25, 2013 at 6:54 AM, Tom Cooksey tom.cooksey@arm.com wrote: > Hi All, > > The final spec has had enum values assigned and been published on Khronos: > > http://www.khronos.org/registry/egl/extensions/EXT/EGL_EXT_image_dma_buf_imp... > > Thanks to all who've provided input.
May I also pull your attention to a detail with the existing spec and Mesa behaviour I am asking about in https://lists.freedesktop.org/archives/mesa-dev/2016-June/120249.html "What is EGL_EXT_image_dma_buf_import image orientation as a GL texture?" Doing a dmabuf import seems to imply an y-flip AFAICT.
I would have expected that *any* egl external image (dma-buf or otherwise) should have native orientation rather than gl orientation. It's somewhat useless otherwise.
In that case importing dmabuf works differently than importing a wl_buffer (wl_drm), because for the latter, the y-invert flag is returned such that the orientation will match GL. And the direct scanout path goes through GBM since you have to import a wl_buffer, and I haven't looked what GBM does wrt. y-flip if anything.
I didn't read it carefully yet (would need caffeine first ;-)) but EGL_KHR_image_base does say "This extension defines a new EGL resource type that is suitable for sharing 2D arrays of image data between client APIs" which to me implies native orientation. So that just sounds like a mesa bug somehow?
That specific sentence implies nothing about orientation to me. Furthermore, the paragraph continues:
"Although the intended purpose is sharing 2D image data, the underlying interface makes no assumptions about the format or purpose of the resource being shared, leaving those decisions to the application and associated client APIs."Might "format" include orientation?
How does "native orientation" connect with "GL texture coordinates"? The latter have explicitly defined orientation and origin. For use in GL, the right way up image is having the origin in the bottom-left corner. An image right way up is an image right way up, regardless which corner is the origin. The problem comes when you start using coordinates.
Do you just get that w/ i965? I know some linaro folks have been using this extension to import buffers from video decoder with freedreno/gallium and no one mentioned the video being upside down.
Intel, yes, but since this happens *only* for the GL import path and direct scanout is fine without y-flipping, I bet people just flipped y and did not think twice, if there even was a problem. I just have a habit of asking "why". ;-)
well, if possible, try with one of the gallium drivers?
I'm honestly not 100% sure what it is supposed to be according to the spec, but I do know some of the linaro folks were doing v4l2dec -> glimagesink with dmabuf with both mali (I think some ST platform?) and freedreno (snapdragon db410c), and no one complained to me that the video was upside down for one or the other. So I guess at least gallium and mali are doing the same thing. No idea if that is the same thing that i965 does.
Hi,
Quentin did some tests for me, and the results are... not what I would have expected: https://phabricator.freedesktop.org/T7475#88454
RadeonSI works like Intel, but Nouveau does the opposite. I think the Nouveau way is correct by the spec, which makes everyone else (intel, radeonsi, weston-simple-dmabuf-v4l) get it wrong. Unfortunately, two wrongs make a right, so when weston-simple-dmabuf-v4l hardcodes Y_INVERT as set, it'll come out the right way on intel and radeon.
oh, wow.. that seems quite odd that two different gallium drivers have different results, since I'd have expected this to be completely handled by mesa/st.. now I'm somewhat curious.
BR, -R
And it is wrong for weston-simple-dmabuf-v4l to set Y_INVERT, that I believe is clear. It is only there because of the "oops, it's upside-down" syndrome, AFAIK.
After all, using GL with windows and FBOs and stuff you very often find yourself upside down, and I suspect people have got the habit of just flipping it if it does not look right the first time. See e.g. the row-order of data going into glTexImage2D...
If the answer is "oops, well, dmabuf import is semantically y-flipping when it should not, but we cannot fix it because that would break everyone", I would be happy with that. I just want confirmation before flipping the flip flag. :-)
So many bugs that accidentally counter each other...
Thanks, pq
On Mon, 20 Jun 2016 09:45:26 -0400 Rob Clark robdclark@gmail.com wrote:
On Mon, Jun 20, 2016 at 8:37 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
On Fri, 17 Jun 2016 11:44:34 -0400 Rob Clark robdclark@gmail.com wrote:
On Fri, Jun 17, 2016 at 9:31 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
On Fri, 17 Jun 2016 08:26:04 -0400 Rob Clark robdclark@gmail.com wrote:
On Fri, Jun 17, 2016 at 3:59 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
On Thu, 16 Jun 2016 10:40:51 -0400 Rob Clark robdclark@gmail.com wrote: > So, if we wanted to extend this to support the fourcc-modifiers that > we have on the kernel side for compressed/tiled/etc formats, what > would be the right approach? > > A new version of the existing extension or a new > EGL_EXT_image_dma_buf_import2 extension, or ??
Hi Rob,
there are actually several things it might be nice to add:
a fourth plane, to match what DRM AddFB2 supports
the 64-bit fb modifiers
queries for which pixel formats are supported by EGL, so a display server can tell the applications that before the application goes and tries with a random bunch of them, shooting in the dark
queries for which modifiers are supported for each pixel format, ditto
I discussed these with Emil in the past, and it seems an appropriate approach might be the following.
Adding the 4th plane can be done as revising the existing EGL_EXT_image_dma_buf_import extension. The plane count is tied to pixel formats (and modifiers?), so the user does not need to know specifically whether the EGL implementation could handle a 4th plane or not. It is implied by the pixel format.
Adding the fb modifiers needs to be a new extension, so that users can tell if they are supported or not. This is to avoid the following false failure: if user assumes modifiers are always supported, it will (may?) provide zero modifiers explicitly. If EGL implementation does not handle modifiers this would be rejected as unrecognized attributes, while if the zero modifiers were not given explicitly, everything would just work.
hmm, if we design it as "not passing modifier" == "zero modifier", and "never explicitly pass a zero modifier" then modifiers could be added without a new extension. Although I agree that queries would need a new extension.. so perhaps not worth being clever.
Indeed.
The queries obviously(?) need a new extension. It might make sense to bundle both modifier support and the queries in the same new extension.
We have some rough old WIP code at https://git.collabora.com/cgit/user/lfrb/mesa.git/log/?h=T1410-modifiers https://git.collabora.com/cgit/user/lfrb/egl-specs.git/log/?h=T1410
> On Mon, Feb 25, 2013 at 6:54 AM, Tom Cooksey tom.cooksey@arm.com wrote: > > Hi All, > > > > The final spec has had enum values assigned and been published on Khronos: > > > > http://www.khronos.org/registry/egl/extensions/EXT/EGL_EXT_image_dma_buf_imp... > > > > Thanks to all who've provided input.
May I also pull your attention to a detail with the existing spec and Mesa behaviour I am asking about in https://lists.freedesktop.org/archives/mesa-dev/2016-June/120249.html "What is EGL_EXT_image_dma_buf_import image orientation as a GL texture?" Doing a dmabuf import seems to imply an y-flip AFAICT.
I would have expected that *any* egl external image (dma-buf or otherwise) should have native orientation rather than gl orientation. It's somewhat useless otherwise.
In that case importing dmabuf works differently than importing a wl_buffer (wl_drm), because for the latter, the y-invert flag is returned such that the orientation will match GL. And the direct scanout path goes through GBM since you have to import a wl_buffer, and I haven't looked what GBM does wrt. y-flip if anything.
I didn't read it carefully yet (would need caffeine first ;-)) but EGL_KHR_image_base does say "This extension defines a new EGL resource type that is suitable for sharing 2D arrays of image data between client APIs" which to me implies native orientation. So that just sounds like a mesa bug somehow?
That specific sentence implies nothing about orientation to me. Furthermore, the paragraph continues:
"Although the intended purpose is sharing 2D image data, the underlying interface makes no assumptions about the format or purpose of the resource being shared, leaving those decisions to the application and associated client APIs."Might "format" include orientation?
How does "native orientation" connect with "GL texture coordinates"? The latter have explicitly defined orientation and origin. For use in GL, the right way up image is having the origin in the bottom-left corner. An image right way up is an image right way up, regardless which corner is the origin. The problem comes when you start using coordinates.
Do you just get that w/ i965? I know some linaro folks have been using this extension to import buffers from video decoder with freedreno/gallium and no one mentioned the video being upside down.
Intel, yes, but since this happens *only* for the GL import path and direct scanout is fine without y-flipping, I bet people just flipped y and did not think twice, if there even was a problem. I just have a habit of asking "why". ;-)
well, if possible, try with one of the gallium drivers?
I'm honestly not 100% sure what it is supposed to be according to the spec, but I do know some of the linaro folks were doing v4l2dec -> glimagesink with dmabuf with both mali (I think some ST platform?) and freedreno (snapdragon db410c), and no one complained to me that the video was upside down for one or the other. So I guess at least gallium and mali are doing the same thing. No idea if that is the same thing that i965 does.
Hi,
Quentin did some tests for me, and the results are... not what I would have expected: https://phabricator.freedesktop.org/T7475#88454
RadeonSI works like Intel, but Nouveau does the opposite. I think the Nouveau way is correct by the spec, which makes everyone else (intel, radeonsi, weston-simple-dmabuf-v4l) get it wrong. Unfortunately, two wrongs make a right, so when weston-simple-dmabuf-v4l hardcodes Y_INVERT as set, it'll come out the right way on intel and radeon.
oh, wow.. that seems quite odd that two different gallium drivers have different results, since I'd have expected this to be completely handled by mesa/st.. now I'm somewhat curious.
Hi,
after a head-scratching session on #dri-devel and a little bit on #wayland too, I'm ready to punt that off as a bad test.
It is quite possible the machine running nouveau had a webcam that really produces upside-down images. weston-simple-dmabuf-v4l does not understand that. Apparently mpv OTOH does. How, maybe there is an answer in V4L2 API, but I haven't looked it up yet.
If we look at the Vivid tests, the results are consistent and expected. All intel, nouveau and radeon work the same way.
And it is wrong for weston-simple-dmabuf-v4l to set Y_INVERT, that I believe is clear. It is only there because of the "oops, it's upside-down" syndrome, AFAIK.
After all, using GL with windows and FBOs and stuff you very often find yourself upside down, and I suspect people have got the habit of just flipping it if it does not look right the first time. See e.g. the row-order of data going into glTexImage2D...
If the answer is "oops, well, dmabuf import is semantically y-flipping when it should not, but we cannot fix it because that would break everyone", I would be happy with that. I just want confirmation before flipping the flip flag. :-)
So many bugs that accidentally counter each other...
Seems like we can conclude this by saying that a dmabuf imported via EGL as a GL texture will have the origin at top-left, instead of what the GL spec says.
Thanks, pq
linaro-mm-sig@lists.linaro.org
-
Pekka Paalanen -
Rob Clark