Re: [PATCH 1/2] media: docs-rst: Document memory-to-memory video decoder interface

[Philipp Zabel]

On Thu, 2018-07-26 at 19:20 +0900, Tomasz Figa wrote:
[...]
> > You might want to mention that if there are insufficient buffers, then
> > VIDIOC_CREATE_BUFS can be used to add more buffers.
> > 
> 
> This might be a bit tricky, since at least s5p-mfc and coda can only
> work on a fixed buffer set and one would need to fully reinitialize
> the decoding to add one more buffer, which would effectively be the
> full resolution change sequence, as below, just with REQBUFS(0),
> REQBUFS(N) replaced with CREATE_BUFS.

The coda driver supports CREATE_BUFS on the decoder CAPTURE queue.

The firmware indeed needs a fixed frame buffer set, but these buffers
are internal only and in a coda specific tiling format. The content of
finished internal buffers is copied / detiled into the external CAPTURE
buffers, so those can be added at will.

regards
Philipp