Re: [PATCH v2 2/2] arm64: dts: qcom: sm8650: setup gpu thermal with higher temperatures

[Neil Armstrong <neil.armstrong@xxxxxxxxxx>]

Hi,

On 13/01/2025 11:28, Akhil P Oommen wrote:
> On 1/10/2025 4:06 PM, Neil Armstrong wrote:
> > On the SM8650, the dynamic clock and voltage scaling (DCVS) for the GPU
> > is done in an hardware controlled loop by the GPU Management Unit (GMU).
> >
> > Since the GMU does a better job at maintaining the GPUs temperature in an
> > acceptable range by taking in account more parameters like the die
> > characteristics or other internal sensors, it makes no sense to try
> > and reproduce a similar set of constraints with the Linux devfreq thermal
> > core.
>
> Just FYI, this description is incorrect. SM8650's GMU doesn't do any
> sort of thermal management.

Ok, thx for confirming this, in our tests the temperature steadily stayed
at a max trip point when setting them higher. But perhaps it's a side effect
of other mitigations.

Are the new trip points still ok ? they are derived from the downstream DT.

Thanks,
Neil

> -Akhil.
>
> > Instead, set higher temperatures in the GPU trip points corresponding to
> > the temperatures provided by Qualcomm in the dowstream source, which will
> > trigger the devfreq thermal core if the GMU cannot handle the temperature
> > surge, and try our best to avoid reaching the critical temperature trip
> > point which should trigger an inevitable thermal shutdown.
> >
> > Fixes: 497624ed5506 ("arm64: dts: qcom: sm8650: Throttle the GPU when overheating")
> > Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
> > ---
> >   arch/arm64/boot/dts/qcom/sm8650.dtsi | 48 ++++++++++++++++++------------------
> >   1 file changed, 24 insertions(+), 24 deletions(-)
> >
> > diff --git a/arch/arm64/boot/dts/qcom/sm8650.dtsi b/arch/arm64/boot/dts/qcom/sm8650.dtsi
> > index 95509ce2713d4fcc3dbe0c5cd5827312d5681af4..e9fcf05cb084b7979ecf0f4712fed332e9f4b07a 100644
> > --- a/arch/arm64/boot/dts/qcom/sm8650.dtsi
> > +++ b/arch/arm64/boot/dts/qcom/sm8650.dtsi
> > @@ -6173,19 +6173,19 @@ map0 {
> >   
> >   			trips {
> >   				gpu0_alert0: trip-point0 {
> > -					temperature = <85000>;
> > +					temperature = <95000>;
> >   					hysteresis = <1000>;
> >   					type = "passive";
> >   				};
> >   
> >   				trip-point1 {
> > -					temperature = <90000>;
> > +					temperature = <115000>;
> >   					hysteresis = <1000>;
> >   					type = "hot";
> >   				};
> >   
> >   				trip-point2 {
> > -					temperature = <110000>;
> > +					temperature = <125000>;
> >   					hysteresis = <1000>;
> >   					type = "critical";
> >   				};
> > @@ -6206,19 +6206,19 @@ map0 {
> >   
> >   			trips {
> >   				gpu1_alert0: trip-point0 {
> > -					temperature = <85000>;
> > +					temperature = <95000>;
> >   					hysteresis = <1000>;
> >   					type = "passive";
> >   				};
> >   
> >   				trip-point1 {
> > -					temperature = <90000>;
> > +					temperature = <115000>;
> >   					hysteresis = <1000>;
> >   					type = "hot";
> >   				};
> >   
> >   				trip-point2 {
> > -					temperature = <110000>;
> > +					temperature = <125000>;
> >   					hysteresis = <1000>;
> >   					type = "critical";
> >   				};
> > @@ -6239,19 +6239,19 @@ map0 {
> >   
> >   			trips {
> >   				gpu2_alert0: trip-point0 {
> > -					temperature = <85000>;
> > +					temperature = <95000>;
> >   					hysteresis = <1000>;
> >   					type = "passive";
> >   				};
> >   
> >   				trip-point1 {
> > -					temperature = <90000>;
> > +					temperature = <115000>;
> >   					hysteresis = <1000>;
> >   					type = "hot";
> >   				};
> >   
> >   				trip-point2 {
> > -					temperature = <110000>;
> > +					temperature = <125000>;
> >   					hysteresis = <1000>;
> >   					type = "critical";
> >   				};
> > @@ -6272,19 +6272,19 @@ map0 {
> >   
> >   			trips {
> >   				gpu3_alert0: trip-point0 {
> > -					temperature = <85000>;
> > +					temperature = <95000>;
> >   					hysteresis = <1000>;
> >   					type = "passive";
> >   				};
> >   
> >   				trip-point1 {
> > -					temperature = <90000>;
> > +					temperature = <115000>;
> >   					hysteresis = <1000>;
> >   					type = "hot";
> >   				};
> >   
> >   				trip-point2 {
> > -					temperature = <110000>;
> > +					temperature = <125000>;
> >   					hysteresis = <1000>;
> >   					type = "critical";
> >   				};
> > @@ -6305,19 +6305,19 @@ map0 {
> >   
> >   			trips {
> >   				gpu4_alert0: trip-point0 {
> > -					temperature = <85000>;
> > +					temperature = <95000>;
> >   					hysteresis = <1000>;
> >   					type = "passive";
> >   				};
> >   
> >   				trip-point1 {
> > -					temperature = <90000>;
> > +					temperature = <115000>;
> >   					hysteresis = <1000>;
> >   					type = "hot";
> >   				};
> >   
> >   				trip-point2 {
> > -					temperature = <110000>;
> > +					temperature = <125000>;
> >   					hysteresis = <1000>;
> >   					type = "critical";
> >   				};
> > @@ -6338,19 +6338,19 @@ map0 {
> >   
> >   			trips {
> >   				gpu5_alert0: trip-point0 {
> > -					temperature = <85000>;
> > +					temperature = <95000>;
> >   					hysteresis = <1000>;
> >   					type = "passive";
> >   				};
> >   
> >   				trip-point1 {
> > -					temperature = <90000>;
> > +					temperature = <115000>;
> >   					hysteresis = <1000>;
> >   					type = "hot";
> >   				};
> >   
> >   				trip-point2 {
> > -					temperature = <110000>;
> > +					temperature = <125000>;
> >   					hysteresis = <1000>;
> >   					type = "critical";
> >   				};
> > @@ -6371,19 +6371,19 @@ map0 {
> >   
> >   			trips {
> >   				gpu6_alert0: trip-point0 {
> > -					temperature = <85000>;
> > +					temperature = <95000>;
> >   					hysteresis = <1000>;
> >   					type = "passive";
> >   				};
> >   
> >   				trip-point1 {
> > -					temperature = <90000>;
> > +					temperature = <115000>;
> >   					hysteresis = <1000>;
> >   					type = "hot";
> >   				};
> >   
> >   				trip-point2 {
> > -					temperature = <110000>;
> > +					temperature = <125000>;
> >   					hysteresis = <1000>;
> >   					type = "critical";
> >   				};
> > @@ -6404,19 +6404,19 @@ map0 {
> >   
> >   			trips {
> >   				gpu7_alert0: trip-point0 {
> > -					temperature = <85000>;
> > +					temperature = <95000>;
> >   					hysteresis = <1000>;
> >   					type = "passive";
> >   				};
> >   
> >   				trip-point1 {
> > -					temperature = <90000>;
> > +					temperature = <115000>;
> >   					hysteresis = <1000>;
> >   					type = "hot";
> >   				};
> >   
> >   				trip-point2 {
> > -					temperature = <110000>;
> > +					temperature = <125000>;
> >   					hysteresis = <1000>;
> >   					type = "critical";
> >   				};