Re: [PATCH 6/6] drm/msm/a6xx: Limit GXPD votes to recovery in A8x

[Akhil P Oommen]

On 4/7/2026 4:31 PM, Konrad Dybcio wrote:
> On 4/7/26 11:30 AM, Taniya Das wrote:
>> From: Akhil P Oommen <akhilpo@xxxxxxxxxxxxxxxx>
>>
>> In A8x GPUs, the GX GDSC is moved to a separate block called GXCLKCTL
>> which is under the GX power domain. Due to the way the support for this
>> block is implemented in its driver, pm_runtime votes result in a vote on
>> GX/GMxC/MxC rails from the APPS RSC. This is against the Adreno
>> architecture which require GMU to be the sole voter of these collapsible
>> rails on behalf of GPU, except during the GPU/GMU recovery.
>>
>> To align with this architectural requirement and to realize the power
>> benefits of the IFPC feature, remove the GXPD votes during gmu resume
>> and suspend. And during the recovery sequence, enable/disable the GXPD
>> along with the 'synced_poweroff' genpd hint to force collapse this GDSC.
>>
>> Signed-off-by: Akhil P Oommen <akhilpo@xxxxxxxxxxxxxxxx>
>> Signed-off-by: Taniya Das <taniya.das@xxxxxxxxxxxxxxxx>
>> ---
> 
> Can we simply make this change unconditional on the gen, so as not to
> maintain 2 separate code paths that try to achieve mostly the same thing?

We can skip the gdsc vote on A8x because the 'gdsc disable' callback is
dummy when the synced_poweroff hint is not set. Otherwise, gdsc may get
disabled during system resume while GMU assumes the ownership. Taniya
touched upon this point in the cover letter:

"""
when GX GDSC is managed through the generic GenPD runtime PM
framework, it can be unintentionally disabled by the OS during system
resume (resume_noirq/complete phases) or runtime PM suspend paths.
"""

-Akhil.

> 
> Konrad