Re: [PATCH] media: venus: assign unique bus_info strings for encoder and decoder

Konrad Dybcio
2025-11-27T18:34:51Z

On 11/27/25 6:11 PM, Jorge Ramirez wrote:
> On 27/11/25 12:47:19, Konrad Dybcio wrote:
>> On 11/25/25 1:55 PM, Jorge Ramirez wrote:
>>> On 21/11/25 20:22:13, Konrad Dybcio wrote:
>>>> On 11/21/25 7:43 PM, Jorge Ramirez-Ortiz wrote:
>>>>> The Venus encoder and decoder video devices currently report the same
>>>>> bus_info string ("platform:qcom-venus").
>>>>>
>>>>> Assign unique bus_info identifiers by appending ":dec" and ":enc" to the
>>>>> parent device name. With this change v4l2-ctl will display two separate
>>>>> logical devices
>>>>>
>>>>> Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez@oss.qualcomm.com>
>>>>> ---
>>>>
>>>> Perhaps that's a stupid question, but is there a reason they're
>>>> separate at all?
>>>
>>> not sure I understand, enc/dec support different APIs, v4l2 controls..is
>>> that what you mean?
>>
>> Perhaps that shows my lack of knowledge about V4L2. I had imagined that
>> a single video device could implement (non-colliding) enc_xyz and dec_xyz
>> operations and was wondering why we need two.
>>
>
> I think the main issue is that the pipelines have very different
> flows/states and semantics so even if the IP block serves both, the
> v4l2 abstraction needs to have them separate (plus we want concurrency).

Ah right, that makes sense

Thanks!

Konrad