Re: [PATCH] media: verisilicon: Explicitly disable all encoder ioctls for decoders

[Nicolas Dufresne <nicolas.dufresne@collabora.com>]

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Le mercredi 27 août 2025 à 18:11 +0200, Paul Kocialkowski a écrit :
> Hi Nicolas,
> 
> On Wed 27 Aug 25, 10:30, Nicolas Dufresne wrote:
> > Hi Paul,
> > 
> > Le mardi 26 août 2025 à 21:04 +0200, Paul Kocialkowski a écrit :
> > > Call the dedicated v4l2_disable_ioctl helper instead of manually
> > > checking whether the current context is an encoder for the selection
> > > ioctls.
> > > 
> > > Signed-off-by: Paul Kocialkowski <paulk@sys-base.io>
> > > ---
> > >  drivers/media/platform/verisilicon/hantro_drv.c  | 2 ++
> > >  drivers/media/platform/verisilicon/hantro_v4l2.c | 6 ++----
> > >  2 files changed, 4 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/drivers/media/platform/verisilicon/hantro_drv.c
> > > b/drivers/media/platform/verisilicon/hantro_drv.c
> > > index 4cc9d00fd293..6fb28a6293e7 100644
> > > --- a/drivers/media/platform/verisilicon/hantro_drv.c
> > > +++ b/drivers/media/platform/verisilicon/hantro_drv.c
> > > @@ -916,6 +916,8 @@ static int hantro_add_func(struct hantro_dev *vpu,
> > > unsigned int funcid)
> > >  		vpu->decoder = func;
> > >  		v4l2_disable_ioctl(vfd, VIDIOC_TRY_ENCODER_CMD);
> > >  		v4l2_disable_ioctl(vfd, VIDIOC_ENCODER_CMD);
> > > +		v4l2_disable_ioctl(vfd, VIDIOC_G_SELECTION);
> > > +		v4l2_disable_ioctl(vfd, VIDIOC_S_SELECTION);
> > 
> > Disabling this IOCTL for JPEG is fine, but for VP8, H.264, HEVC, VP9 and
> > AV1, it
> > is pretty much mandatory. Otherwise your stream will advertise the padded
> > dimentions and there would be no way to tell it that what is the cropping
> > window
> > for bitstream generation purpose.
> 
> Maybe the lack of context around the patch doesn't make it clear, but this is
> to disable the ioctls for decoders (not encoders), which don't need to use the
> selection API. This keeps the ioctls enabled and available for all encoders.

My bad, miss-read. I think you could reduce the confusion with a subject line
that is narrower:

  media: verisilicon: Explicitly disable SELECTION API ioctl for decoders

And you can add:

Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>

cheers,
Nicolas

> 
> > Considering you are looking forward adding H.264 encoding, do you really
> > want
> > to apply this fix ?
> 
> I am well aware that this is required to setup the crop in the coded bitstream
> and I am definitely using it in my encoding work :)
> 
> Cheers,
> 
> Paul
> 
> > 
> > Nicolas
> > 
> > >  	}
> > >  
> > >  	video_set_drvdata(vfd, vpu);
> > > diff --git a/drivers/media/platform/verisilicon/hantro_v4l2.c
> > > b/drivers/media/platform/verisilicon/hantro_v4l2.c
> > > index 6bcd892e7bb4..fcf3bd9bcda2 100644
> > > --- a/drivers/media/platform/verisilicon/hantro_v4l2.c
> > > +++ b/drivers/media/platform/verisilicon/hantro_v4l2.c
> > > @@ -663,8 +663,7 @@ static int vidioc_g_selection(struct file *file, void
> > > *priv,
> > >  	struct hantro_ctx *ctx = file_to_ctx(file);
> > >  
> > >  	/* Crop only supported on source. */
> > > -	if (!ctx->is_encoder ||
> > > -	    sel->type != V4L2_BUF_TYPE_VIDEO_OUTPUT)
> > > +	if (sel->type != V4L2_BUF_TYPE_VIDEO_OUTPUT)
> > >  		return -EINVAL;
> > >  
> > >  	switch (sel->target) {
> > > @@ -696,8 +695,7 @@ static int vidioc_s_selection(struct file *file, void
> > > *priv,
> > >  	struct vb2_queue *vq;
> > >  
> > >  	/* Crop only supported on source. */
> > > -	if (!ctx->is_encoder ||
> > > -	    sel->type != V4L2_BUF_TYPE_VIDEO_OUTPUT)
> > > +	if (sel->type != V4L2_BUF_TYPE_VIDEO_OUTPUT)
> > >  		return -EINVAL;
> > >  
> > >  	/* Change not allowed if the queue is streaming. */
> 
> 

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