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

[bod]

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.


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