Le jeudi 31 octobre 2024 à 11:26 +0100, Hans Verkuil a écrit : > On 10/31/24 11:11, Laurent Pinchart wrote: > > Hi Hans, > > > > Thank you for the patch. > > > > On Thu, Oct 31, 2024 at 08:50:04AM +0100, Hans Verkuil wrote: > > > Clearly state that the V4L2_CID_MIN_BUFFERS_FOR_OUTPUT and > > > V4L2_CID_MIN_BUFFERS_FOR_CAPTURE controls are required for > > > stateful codecs. > > > > Wouldn't it be better for this kind of information to be centralized in > > a stateful decoder document ? That would make it easier for developers > > to see all they need to implement. Otherwise they would need to read > > through the whole documentation to pick the parts of the API they need > > to support in their drivers. > > It's also already mentioned in the documentation for the stateful de/encoders here: > > https://linuxtv.org/downloads/v4l-dvb-apis-new/userspace-api/v4l/dev-mem2mem.html > > Also, once this vicodec patch is merged: > > https://patchwork.linuxtv.org/project/linux-media/patch/1dd09050-40ca-4c5b-b985-819731140388@xxxxxxxxx/ > > I plan to push v4l2-compliance patches that explicitly test for the presence of > these controls and fail if they are missing (like they are now in vicodec). Thanks, this is a great idea. Nicolas > > Regards, > > Hans > > > > > > Signed-off-by: Hans Verkuil <hverkuil@xxxxxxxxx> > > > --- > > > Documentation/userspace-api/media/v4l/control.rst | 6 ++++-- > > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > > > diff --git a/Documentation/userspace-api/media/v4l/control.rst b/Documentation/userspace-api/media/v4l/control.rst > > > index 57893814a1e5..9253cc946f02 100644 > > > --- a/Documentation/userspace-api/media/v4l/control.rst > > > +++ b/Documentation/userspace-api/media/v4l/control.rst > > > @@ -290,13 +290,15 @@ Control IDs > > > This is a read-only control that can be read by the application and > > > used as a hint to determine the number of CAPTURE buffers to pass to > > > REQBUFS. The value is the minimum number of CAPTURE buffers that is > > > - necessary for hardware to work. > > > + necessary for hardware to work. This control is required for stateful > > > + decoders. > > > > > > ``V4L2_CID_MIN_BUFFERS_FOR_OUTPUT`` ``(integer)`` > > > This is a read-only control that can be read by the application and > > > used as a hint to determine the number of OUTPUT buffers to pass to > > > REQBUFS. The value is the minimum number of OUTPUT buffers that is > > > - necessary for hardware to work. > > > + necessary for hardware to work. This control is required for stateful > > > + encoders. > > > > > > .. _v4l2-alpha-component: > > > > > >
