Re: [PATCH v2 2/4] arm64: dts: allwinner: h6: Add cooling map for GPU

Hi Samuel,

On Tue, 23 Aug 2022 at 05:16, Samuel Holland [off-list ref] wrote:

On 8/21/22 12:30 PM, Clément Péron wrote:

quoted

Add a simple cooling map for the GPU.

It would be good to document where the trip point temperatures came from.

If I remember correctly, I got those when getting the dtb from my
Beelink GS1 when it was running vendor Android with the oldest
Allwinner kernel.

But now that you ask I double check with the "new" vendor kernel source:
https://github.com/Allwinner-Homlet/H6-BSP4.9-linux/blob/master/arch/arm64/boot/dts/sunxi/sun50iw6p1.dtsi#L2034-L2053

And It's different from what I got in the past.
The throttling starts when the GPU is already very hot (95, 100 and
105°C) and seems to only disable the highest frequency (756, 624 and
576MHz).
Which let the GPU running at 0.91V @ 540MHz.

Which is far to be the lowest possible consumption for the GPU (0.81V
@ 336MHz would be better in the hottest situation)

I'm not an expert but either I could just try to copy/paste the same
behavior or try to have a more smooth cooling map (70, 85, 100°C).

What do you think?

Thanks,
Clement

quoted

Signed-off-by: Clément Péron <redacted>

Acked-by: Samuel Holland <samuel@sholland.org>

quoted

---
 arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi | 22 ++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi
index 5a28303d3d4c..943ae5374dd6 100644
--- a/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi
+++ b/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi

@@ -186,6 +186,7 @@ gpu: gpu@1800000 {
                      clocks = <&ccu CLK_GPU>, <&ccu CLK_BUS_GPU>;
                      clock-names = "core", "bus";
                      resets = <&ccu RST_BUS_GPU>;
+                     #cooling-cells = <2>;
                      status = "disabled";
              };

@@ -1075,6 +1076,27 @@ gpu-thermal {
                      polling-delay-passive = <0>;
                      polling-delay = <0>;
                      thermal-sensors = <&ths 1>;
+
+                     trips {
+                             gpu_alert: gpu-alert {
+                                     temperature = <85000>;
+                                     hysteresis = <2000>;
+                                     type = "passive";
+                             };
+
+                             gpu-crit {
+                                     temperature = <100000>;
+                                     hysteresis = <0>;
+                                     type = "critical";
+                             };
+                     };
+
+                     cooling-maps {
+                             map0 {
+                                     trip = <&gpu_alert>;
+                                     cooling-device = <&gpu THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
+                             };
+                     };
              };
      };
 };

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