Jason,
From my point of view wl_drm isn't link to Mesa, it is only about
exchange buffers by using a file descriptor and, for example, doesn't rely on EGL.
I understand that other graphic stacks could have defined their own way to for zero-copy (and so other protocols). I don't aim to make gstreamer wayland sink works for all of them but at least with wl_drm protocol which is quite generic.
Since dmabuf has been adopted in kernel we have the opportunity to rationalize also some code in userland and for that we need a common wayland protocol. Move wl_drm into wayland-core make it more easily accessible for all software even for those who don't use Mesa.
Benjamin
PS: I have an updated version of my patch for latest wayland
2013/11/27 Jasper St. Pierre jstpierre@mecheye.net:
Wasn't EGLStreams supposed to solve the use case of passing hardware buffers around in a standard way?
On Wed, Nov 27, 2013 at 1:22 PM, Jason Ekstrand jason@jlekstrand.net wrote:
On Nov 27, 2013 10:53 AM, "Benjamin Gaignard" benjamin.gaignard@linaro.org wrote:
Hi all,
I'm working for Linaro on enabling a zero copy path in GStreamer by using dmabuf. To make this possible I have patched gst wayland sink to use wayland drm protocol: https://bugzilla.gnome.org/show_bug.cgi?id=711155
Today wayland drm protocol is limited to Mesa so I have decided to move it into wayland-core. My hardware doesn't have gpu support yet so I have patched weston (pixman) to allow usage of wl_drm buffers. With this I able to share/use a buffer allocated by DRM in gstreamer pipeline even if I don't have gpu and EGL.
What do you think about make wayland drm protocol available like this ?
Benjamin,
The problem here is that wl_drm is really a mesa extension. Well, more of an open-source linux graphics stack extension. The point is that there are other graphics stacks: Rhaspberry Pi, libhybris, other proprietary stacks, etc. and each of these graphics stacks has its own extension for passing hardware buffers around. This means that if you want your GStreamer sink to work on these other stacks with zero-copy, you will have to talk their protocols. Because wl_drm isn't global to all of wayland, it probably shouldn't go into the wayland core.
This does not mean, however, that wl_drm can't be exposed in a more sensible way. As of 1.3, we are now exporting wayland.xml to /usr/share/wayland and we can put other extensions there as well. We could have, for instance, a /usr/share/mesa.xml file that provides the mesa extensions. Then projects wanting to talk directly to mesa can generate the header and C files from the system-installed xml file. This would solve the problem of keeping everything in sync.
One last note (this one's been bugging me for a while). If we are going to export wl_drm in some way, we should probably rename it to something like mesa_drm. We really need to get out of the habit of using the wl_ namespace for everything that talks the wayland protocol. If we don't alter the details of wl_drm in the rename, it shouldn't be too hard to move everyone over from wl_drm to mesa_drm.
Hope that's sensible/helpful. --Jason Ekstrand
wayland-devel mailing list wayland-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/wayland-devel
-- Jasper