Hi Jesse,
Thank you for the review.
On Wednesday 20 June 2012 08:09:19 Jesse Barker wrote:
Laurent,
Your recent documentation efforts are extremely commendable. Just a couple of small nits below...
On Wed, Jun 20, 2012 at 7:09 AM, Laurent Pinchart
laurent.pinchart@ideasonboard.com wrote:
Add support for the dma-buf exporter role to the frame buffer API. The importer role isn't meaningful for frame buffer devices, as the frame buffer device model doesn't allow using externally allocated memory.
Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com
Documentation/fb/api.txt | 36 ++++++++++++++++++++++++++++++++++++ drivers/video/fbmem.c | 36 ++++++++++++++++++++++++++++++++++++ include/linux/fb.h | 12 ++++++++++++ 3 files changed, 84 insertions(+), 0 deletions(-)
diff --git a/Documentation/fb/api.txt b/Documentation/fb/api.txt index d4ff7de..f0b2173 100644 --- a/Documentation/fb/api.txt +++ b/Documentation/fb/api.txt @@ -304,3 +304,39 @@ extensions. Upon successful format configuration, drivers update the fb_fix_screeninfo type, visual and line_length fields depending on the selected format. The type and visual fields are set to FB_TYPE_FOURCC and FB_VISUAL_FOURCC respectively. +
+5. DMA buffer sharing +---------------------
+The dma-buf kernel framework allows DMA buffers to be shared across devices +and applications. Sharing buffers across display devices and video capture or +video decoding devices allow zero-copy operation when displaying video content +produced by a hardware device such as a camera or a hardware codec. This is +crucial to achieve optimal system performances during video display. + +While dma-buf supports both exporting internally allocated memory as a dma-buf +object (known as the exporter role) and importing a dma-buf object to be used +as device memory (known as the importer role), the frame buffer API only +supports the exporter role, as the frame buffer device model doesn't support +using externally-allocated memory.
+The export a frame buffer as a dma-buf file descriptors, applications call the
s/The/To s/descriptors/descriptor
Fixed, thanks.