Re: [PATCH 1/2] media: venus: vdec: signal EOS with a real buffer

[David Heidelberg]

On 09/10/2026 11:15, bod@xxxxxxxxxx wrote:
> On 2026-09-28 23:40 +0200, David Heidelberg wrote:
> > The decoder tells the firmware about the end of the stream with an empty
> > buffer command whose address is a dummy (0xdeadb000), because the host
> > has no input buffer to name. The SDM845 (Venus v4) firmware validates
> > that address and rejects it:
> >
> >    IsBufferProtected(1087): VenusCoreCtrl: CP_UNKNOWN, buffer straddles
> >    CP & non-CP regions
> >    vDec_EmptyBuffer(1932): Invalidate buffer in ETB
> >
> > and raises HFI_ERR_SESSION_FATAL, reported by the driver as
> >
> >    qcom-venus aa00000.video-codec: session error: event id:1001 (deadb000)
> >
> > Both queues are then put into an error state, so the drain never
> > completes and every V4L2_DEC_CMD_STOP ends the stream with an error:
> > GStreamer's poll() fails at end of file, ffmpeg aborts.
> >
> > Allocate a small buffer the first time a decoder instance is drained and
> > use its device address for the EOS command, so the firmware gets an
> > address that is mapped and outside the protected regions. The firmware
> > then drains normally: all frames are returned and the last capture
> > buffer carries V4L2_BUF_FLAG_LAST. The NULL address used by old IRIS2
> > firmware is left alone.
> >
> > Assisted-by: LLM
> > Fixes: beac82904a87 ("media: venus: make decoder compliant with stateful codec API")
> > Signed-off-by: David Heidelberg <david@xxxxxxx>
>
> The logic stacks up as I read it but, I want to see this a) work on sdm845
> and b) not break on sm8250 before applying.

On sdm845 it works great (tested multiple sdm845 phones with `livi --demo-h264` 
and loop enabled. I don't have sm8250, thus that's up to someone with the device :)

David

> Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
> ---
> bod