RE: Re: [PATCH 1/2] dt-bindings: gpu: mali-valhall-csf: Document i.MX952 support

[Guangliu Ding]

Hi Daniel

> On 4/1/26 11:48, Guangliu Ding wrote:
> > [You don't often get email from guangliu.ding@xxxxxxx. Learn why this
> > is important at https://aka.ms/LearnAboutSenderIdentification ]
> >
> > Hi Liviu
> >
> > Thanks for your review. Please refer to my comments below:
> >
> >> On Tue, Mar 31, 2026 at 06:12:38PM +0800, Guangliu Ding wrote:
> >>> Add compatible string of Mali G310 GPU on i.MX952 board.
> >>>
> >>> Signed-off-by: Guangliu Ding <guangliu.ding@xxxxxxx>
> >>> Reviewed-by: Jiyu Yang <jiyu.yang@xxxxxxx>
> >>> ---
> >>>  Documentation/devicetree/bindings/gpu/arm,mali-valhall-csf.yaml | 1
> >>> +
> >>>  1 file changed, 1 insertion(+)
> >>>
> >>> diff --git
> >>> a/Documentation/devicetree/bindings/gpu/arm,mali-valhall-csf.yaml
> >> b/Documentation/devicetree/bindings/gpu/arm,mali-valhall-csf.yaml
> >>> index 8eccd4338a2b..6a10843a26e2 100644
> >>> ---
> >>> a/Documentation/devicetree/bindings/gpu/arm,mali-valhall-csf.yaml
> >>> +++ b/Documentation/devicetree/bindings/gpu/arm,mali-valhall-csf.yam
> >>> +++ l
> >>> @@ -20,6 +20,7 @@ properties:
> >>>            - enum:
> >>>                - mediatek,mt8196-mali
> >>>                - nxp,imx95-mali            # G310
> >>> +              - nxp,imx952-mali           # G310
> >> Can you explain why this is needed? Can it not be covered by the
> >> existing compatible?
> > There are functional differences in GPU module (GPUMIX) between i.MX95
> > and i.MX952. So they cannot be fully covered by a single existing compatible.
> > On i.MX952, The GPU clock is controlled by hardware GPU auto
> > clock-gating mechanism, while the GPU clock is managed explicitly by the
> driver on i.MX95.
> > Because of these behavioral differences, separate compatible strings
> > "nxp,imx95-mali" and "nxp,imx952-mali" are needed to allow the driver
> > to handle the two variants independently and to keep room for future
> divergence.
> 
> 
> This information should be added in the commit message explaining why
> 
> the change is needed.
> 
> 
> But then where is the driver code taking care of these diferences?
> 

Yes. Currently the driver does not require "nxp,imx952-mali" string.
However, when GPU ipa_counters are enabled to calculate the GPU busy_time/idle_time for 
GPU DVFS feature, they will conflict with the hardware GPU auto clock‑gating mechanism, 
causing GPU clock to remain always on.
In such cases, ipa_counters need to be disabled so that the GPU auto clock‑gating 
mechanism can operate normally, using "nxp,imx952-mali" string.