Re: [PATCH] media: venus: vdec: fix error state assignment for zero bytesused

[Renjiang Han]

On 12/7/2025 7:56 AM, Bryan O'Donoghue wrote:
> On 26/11/2025 04:23, Renjiang Han wrote:
> > Previously, the check for zero bytesused and the assignment of error
> > state was performed outside the V4L2_BUF_FLAG_LAST branch, which could
> > incorrectly set the error state during drain operations. 
>
> This deserves more elaboration.
>
> Instead of saying previously - talk about what it currently does and 
> the precise circumstances under which it goes wrong. Try to make the 
> description as plain and concise as possible.
>
> This patch
> > moves the zero-bytesused check inside the 'else' branch, ensuring that
> > the error state is only set for non-EOS buffers with zero payload.
> >
> > Additionally, the patch keeps the rest of the buffer state handling
> > logic unchanged, including handling of HFI_BUFFERFLAG_DATACORRUPT and
> > HFI_BUFFERFLAG_DROP_FRAME.
>
> I don't think you need to tell us what's not touched in your commit log.
>
> - Tell us what is wrong directly and plainly.
>   Include how the bug you are fixing can come about i.e. under what
>   circumstances we would see the error.
>
> - Then tell us how you've fixed it.
>
> - And include a Fixes: tag please.
>   Since this is a bug fix you are proposing, it needs to be backported.
sure, thanks for your comments.
> > Signed-off-by: Renjiang Han <renjiang.han@xxxxxxxxxxxxxxxx>
> > ---
> > This patch refines the error state assignment logic in the Venus vdec
> > driver for Qualcomm platforms. Specifically, it ensures that the buffer
> > state is only set to VB2_BUF_STATE_ERROR for non-EOS capture buffers
> > with zero bytesused, preventing false error reporting during drain
> > operations.
> > ---
> >   drivers/media/platform/qcom/venus/vdec.c | 6 +++---
> >   1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/media/platform/qcom/venus/vdec.c 
> > b/drivers/media/platform/qcom/venus/vdec.c
> > index 
> > 4a6641fdffcf79705893be58c7ec5cf485e2fab9..d0bd2d86a31f9a18cb68b08ba66affdf8fc5092d 
> > 100644
> > --- a/drivers/media/platform/qcom/venus/vdec.c
> > +++ b/drivers/media/platform/qcom/venus/vdec.c
> > @@ -1440,10 +1440,10 @@ static void vdec_buf_done(struct venus_inst 
> > *inst, unsigned int buf_type,
> >                   inst->drain_active = false;
> >                   inst->codec_state = VENUS_DEC_STATE_STOPPED;
> >               }
> > +        } else {
> > +            if (!bytesused)
> > +                state = VB2_BUF_STATE_ERROR;
> >           }
> > -
> > -        if (!bytesused)
> > -            state = VB2_BUF_STATE_ERROR;
> >       } else {
> >           vbuf->sequence = inst->sequence_out++;
> >       }
> >
> > ---
> > base-commit: 663d0d1af3faefe673cabf4b6b077149a87ad71f
> > change-id: 20251126-fix-error-state-24183a8538cd
> >
> > Best regards,
> > --
> > Renjiang Han <renjiang.han@xxxxxxxxxxxxxxxx>
--
Best regards,
Renjiang Han