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

Jorge Ramirez
2025-11-27T17:11:51Z

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).