Am Montag, 20. Mai 2019, 22:16:46 CEST schrieb Doug Anderson: > Hi, > > On Mon, May 20, 2019 at 10:01 AM Matthias Kaehlcke <mka@xxxxxxxxxxxx> wrote: > > > > On rk3288 the CPU and GPU temperatures are correlated. Limit the GPU > > frequency on veyron mickey to 300 MHz for CPU temperatures >= 85°C. > > > > This matches the configuration of the downstream Chrome OS 3.14 kernel, > > the 'official' kernel for mickey. > > > > Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx> > > --- > > Note: this patch depends on "ARM: dts: rockchip: Add #cooling-cells > > entry for rk3288 GPU" (https://lore.kernel.org/patchwork/patch/1075005/) > > --- > > arch/arm/boot/dts/rk3288-veyron-mickey.dts | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > diff --git a/arch/arm/boot/dts/rk3288-veyron-mickey.dts b/arch/arm/boot/dts/rk3288-veyron-mickey.dts > > index d889ab3c8235..f118d92a49d0 100644 > > --- a/arch/arm/boot/dts/rk3288-veyron-mickey.dts > > +++ b/arch/arm/boot/dts/rk3288-veyron-mickey.dts > > @@ -125,6 +125,12 @@ > > <&cpu2 8 THERMAL_NO_LIMIT>, > > <&cpu3 8 THERMAL_NO_LIMIT>; > > }; > > + > > + /* At very hot, don't let GPU go over 300 MHz */ > > + cpu_very_hot_limit_gpu { > > + trip = <&cpu_alert_very_hot>; > > + cooling-device = <&gpu 2 2>; > > + }; > > Two things: > > A) If I'm reading things properly, you're actually limiting things to > 400 MHz. This is because you don't have <https://crrev.com/c/1574579> > which deletes the 500 MHz GPU operating point. So on upstream the > available points are: > > 0: 600 MHz > 1: 500 MHz > 2: 400 MHz > 3: 300 MHz > 4: 200 MHz > 5: 100 MHz > > ...and downstream: > > 0: 600 MHz > 1: 400 MHz > 2: 300 MHz > 3: 200 MHz > 4: 100 MHz > > Thinking about it more, I bet Heiko would actually be OK deleting the > 500 MHz GPU operating point for veyron. Technically it's not needed > upstream because upstream doesn't have our hacks to allow re-purposing > NPLL for HDMI (so they _can_ make 500 MHz) but maybe we can make the > argument that these laptops have only ever been tested with the 500 > MHz operating point removed and also that eventually someonje will > probably figure out a way to re-purpose NPLL for HDMI even upstream... Yeah. Dropping the opp sounds sensible ... for the npll-related thing and also if you're really running into thermal constraints it might be good to give the system a bit more breathing room? Heiko > B) It seems like in the same patch you'd want to introduce > "cpu_warm_limit_gpu", AKA: > > cpu_warm_limit_gpu { > trip = <&cpu_alert_warm>; > cooling-device = > <&gpu 1 1>; > }; > > > -Doug
