On 1/13/2025 4:15 PM, Neil Armstrong wrote:
> 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.
I don't have expertise on the thermal side. But in my non-expert
opinion, it is fine to use a similar configuration from downstream.
-Akhil.
>
> 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";
>>> };
>>>
>>
>
