Re: [PATCH RFC 00/10] media: qcom: venus: add MSM8939 support

[Konrad Dybcio]

On 4/16/26 3:43 PM, Erikas Bitovtas wrote:
> This patch series adds support for Venus on MSM8939. It is mostly
> similar to MSM8916 Venus, except it needs two additional cores to be
> powered on before it can start decoding.
> 
> This patch series is marked as an RFC. Before submitting a non-RFC
> series, I would like to have some details clarified regarding how Venus
> works in order to improve and eventually upstream support for MSM8939.
> 
> 1. In downstream, particularly in LA.BR.1.2.9.1_rb1.5, the buses
>    for vcodec0 cores have only decoding bits enabled, as depicted
>    by qcom,bus-configs property of qcom,msm-bus-clients children
>    in qcom,vidc node. Do I understand correctly that these cores
>    are only needed for decoding, and not for encoding?
> 2. Currently in device tree there is a video-decoder subnode for Venus
>    node, however, for SDM845-v2 (and newer) chipsets, Venus does not use
>    subnodes. Does this mean it should be dropped for MSM8939 as well?
> 3. MSM8939 supports HEVC decoding, however, as the patchset is written
>    now, it does not work. It can be enabled, however, it will result in
>    breakage of Venus for faulty MSM8916 firmwares, because the code
>    disabling HEVC for HFI v1 needs to be removed, and as per commit
>    c50cc6dc6c48 ("media: venus: hfi_parser: Ignore HEVC encoding for V1"),
>    this would break support for some MSM8916 devices. What could be the
>    best way to work around this?

if (!device_is_compatible(core->dev, "qcom,msm8939-venus"))?

Also, you mentioned HEVC *de*coding, while the commit you pointed to
disables *en*coding (decoding had been already disabled prior to that
commit)

Konrad