Re: [PATCH v2 2/7] media: iris: switch to hardware mode after firmware boot

[Konrad Dybcio]

On 2/27/26 3:11 PM, Vikash Garodia wrote:
> Currently the driver switches the vcodec GDSC to hardware (HW) mode
> before firmware load and boot sequence. GDSC can be powered off, keeping
> in hw mode, thereby the vcodec registers programmed in TrustZone (TZ)
> carry default (reset) values.
> Move the transition to HW mode after firmware load and boot sequence.
> 
> The bug was exposed with driver configuring different stream ids to
> different devices via iommu-map. With registers carrying reset values,
> VPU would not generate desired stream-id, thereby leading to SMMU fault.
> 
> For vpu4, when GDSC is switched to HW mode, there is a need to perform
> the reset operation. Without reset, there are occassional issues of
> register corruption observed. Hence the vpu GDSC switch also involves
> the reset.

Is that a characteristic of the hardware (e.g. also seen downstream), or
is that required with upstream iris only?

Konrad