82019205e3
There is a TODO comment about the dma-buf being mapped in VIDIOC_QBUF instead of doing it closer to when the actual DMA is going to happen when the buffers are queued in the driver (i.e: __enqueue_in_driver). But there is a reason to do it earlier in QBUF, and is that userspace has no way to know if a exported dma-buf can be imported successfully and so relies on QBUF succeeding as indication that the dma-buf mapped. If QBUF fails, the application can fallback to another streaming I/O method. But moving the dma-buf mapping later when queueing the buffers can be too late for userspace to recover, since it may had dropped the buffer(s) already when it knows that the dma-buf mapping failed. So remove the TODO instead and change the comment to explain this. Suggested-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> |
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.. | ||
Kconfig | ||
Makefile | ||
tuner-core.c | ||
v4l2-async.c | ||
v4l2-clk.c | ||
v4l2-common.c | ||
v4l2-compat-ioctl32.c | ||
v4l2-ctrls.c | ||
v4l2-dev.c | ||
v4l2-device.c | ||
v4l2-dv-timings.c | ||
v4l2-event.c | ||
v4l2-fh.c | ||
v4l2-flash-led-class.c | ||
v4l2-ioctl.c | ||
v4l2-mc.c | ||
v4l2-mem2mem.c | ||
v4l2-of.c | ||
v4l2-subdev.c | ||
v4l2-trace.c | ||
vb2-trace.c | ||
videobuf2-core.c | ||
videobuf2-dma-contig.c | ||
videobuf2-dma-sg.c | ||
videobuf2-dvb.c | ||
videobuf2-memops.c | ||
videobuf2-v4l2.c | ||
videobuf2-vmalloc.c | ||
videobuf-core.c | ||
videobuf-dma-contig.c | ||
videobuf-dma-sg.c | ||
videobuf-dvb.c | ||
videobuf-vmalloc.c |