Re: [RFC 3/3] ARM: dts: Don't overheat the Odroid XU3-Lite on high load

From: Krzysztof Kozlowski
Date: Wed Feb 17 2016 - 20:47:35 EST

On 18.02.2016 04:53, Anand Moon wrote:
> Hi Krzysztof,
>
> On 17 February 2016 at 12:25, Krzysztof Kozlowski
> <k.kozlowski@xxxxxxxxxxx> wrote:
>> After adding cpufreq-dt support to Exynos542x, the Odroid XU3-Lite can
>> be easily overheated when launching eight CPU-intensive tasks:
>> thermal thermal_zone3: critical temperature reached(121 C),shutting down
>>
>> This seems to be specific to Odroid XU3-Lite board which officially
>> supports lower frequencies than regular XU3 or XU4. When working at
>> maximum CPU speed (1800 MHz big and 1300 MHz LITTLE) in warmer place for
>> longer time, the fan fails to cool down the board and it reaches
>> critical temperature.
>>
>> Add CPU cooling to Exynos5422/5800 to fix this issue. When reaching 95
>> degrees of Celsius, the board will slow down by 3 steps (around
>> 1400/1000 MHz). When reaching 110 degrees of Celsius go to 600 MHz.
>>
>> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
>> ---
>> arch/arm/boot/dts/exynos5422-cpu-thermal.dtsi | 41 +++++++++++++++++++++++++++
>> 1 file changed, 41 insertions(+)
>>
>> diff --git a/arch/arm/boot/dts/exynos5422-cpu-thermal.dtsi b/arch/arm/boot/dts/exynos5422-cpu-thermal.dtsi
>> index 2b289d7c0d13..66073ce29aee 100644
>> --- a/arch/arm/boot/dts/exynos5422-cpu-thermal.dtsi
>> +++ b/arch/arm/boot/dts/exynos5422-cpu-thermal.dtsi
>> @@ -34,6 +34,16 @@
>> hysteresis = <5000>; /* millicelsius */
>> type = "active";
>> };
>> + cpu_alert3: cpu-alert-3 {
>> + temperature = <95000>; /* millicelsius */
>> + hysteresis = <5000>; /* millicelsius */
>> + type = "passive";
>> + };
>> + cpu_alert4: cpu-alert-4 {
>> + temperature = <110000>; /* millicelsius */
>> + hysteresis = <5000>; /* millicelsius */
>> + type = "passive";
>> + };
>> cpu_crit0: cpu-crit-0 {
>> temperature = <120000>; /* millicelsius */
>> hysteresis = <0>; /* millicelsius */
>> @@ -53,6 +63,37 @@
>> trip = <&cpu_alert2>;
>> cooling-device = <&fan0 2 3>;
>> };
>> +
>> + /*
>> + * When reaching cpu_alert3, reduce CPU
>> + * by 3 steps. On Exynos5422/5800 that would
>> + * be: 1400 MHz and 1000 MHz.
>> + */
>> + map3 {
>> + trip = <&cpu_alert3>;
>> + cooling-device = <&cpu0 3 3>;
>> + };
>> + map4 {
>> + trip = <&cpu_alert3>;
>> + cooling-device = <&cpu4 3 3>;
>> + };
>> +
>> + /*
>> + * When reaching cpu_alert4, reduce CPU
>> + * to 600 MHz (11 steps for big, 7 steps for
>> + * LITTLE).
>> + * Exynos5420 has less OPPs and reversed
>> + * numbering of CPUs (big/LITTLE) so this
>> + * would not match.
>> + */
>> + map5 {
>> + trip = <&cpu_alert4>;
>> + cooling-device = <&cpu0 7 7>;
>> + };
>> + map6 {
>> + trip = <&cpu_alert4>;
>> + cooling-device = <&cpu4 11 11>;
>> + };
>> };
>> };
>> };
>> --
>> 2.5.0
>>
>
> could you append this patch with following changes.

Could you describe why?

> diff --git a/arch/arm/boot/dts/exynos5422-cpu-thermal.dtsi
> b/arch/arm/boot/dts/exynos5422-cpu-thermal.dtsi
> index 66073ce..4e72637 100644
> --- a/arch/arm/boot/dts/exynos5422-cpu-thermal.dtsi
> +++ b/arch/arm/boot/dts/exynos5422-cpu-thermal.dtsi
> @@ -16,8 +16,8 @@
> thermal-zones {
> cpu0_thermal: cpu0-thermal {
> thermal-sensors = <&tmu_cpu0 0>;
> - polling-delay-passive = <0>;
> - polling-delay = <0>;
> + polling-delay-passive = <250>; /* milliseconds */
> + polling-delay = <500>; /* milliseconds */
> trips {
> cpu_alert0: cpu-alert-0 {
> temperature = <50000>; /*
> millicelsius */
> ---
> On running linaro pm-qa diagnostic tool
> ----------------------------------------------------------
>
> thermal_01.28: checking 'thermal_zone2'/'trip_point_2_temp' ='110000'... Ok
> thermal_01.29: checking 'cdev0_trip_point' exists in
> '/sys/devices/virtual/thermal/thermal_zone0'... Ok
> thermal_01.30: checking 'thermal_zone0/cdev0_trip_point' valid binding... Ok
> thermal_01.31: checking 'cdev4_trip_point' exists in
> '/sys/devices/virtual/thermal/thermal_zone0'... Ok
> thermal_01.32: checking 'thermal_zone0/cdev4_trip_point' valid binding... Err
> thermal_01.33: checking 'cdev4_trip_point' exists in
> '/sys/devices/virtual/thermal/thermal_zone0'... Ok
> thermal_01.34: checking 'thermal_zone0/cdev4_trip_point' valid binding... Err
> thermal_01.35: checking 'cdev4_trip_point' exists in
> '/sys/devices/virtual/thermal/thermal_zone0'... Ok
> thermal_01.36: checking 'thermal_zone0/cdev4_trip_point' valid binding... Err
> thermal_01.37: checking 'cdev4_trip_point' exists in
> '/sys/devices/virtual/thermal/thermal_zone0'... Ok
> thermal_01.38: checking 'thermal_zone0/cdev4_trip_point' valid binding... Err
>
> thermal_01: fail
> -------------------------------------------------------
> I also got lot's of error.
>
> root@odroidxu4l:~# cpu[ 3050.847663] cpu cpu4: Failed to find dev_opp: -19
> [ 3171.640836] cpu cpu4: device_opp_debug_create_link: Failed to create link
> [ 3171.646197] cpu cpu4: _add_list_dev: Failed to register opp debugfs (-12)
> [ 3171.653574] cpu cpu7: device_opp_debug_create_link: Failed to create link
> [ 3171.659752] cpu cpu7: _add_list_dev: Failed to register opp debugfs (-12)
> [ 3171.697011] cpu cpu5: cpufreq_init: failed to get clk: -2
> [ 3171.732505] cpu cpu6: cpufreq_init: failed to get clk: -2
> [ 3171.768160] cpu cpu7: cpufreq_init: failed to get clk: -2
>
> Tested on Odroid-XU4
>
> Reviewed-by: Anand Moon <linux.amoon@xxxxxxxxx>
> Tested-by: Anand Moon <linux.amoon@xxxxxxxxx>

The patch is not sufficient. It does not work the way it should...

BTW, I found the issue. The order of trip points in DT:
thermal_zone0/trip_point_0_hyst:5000
thermal_zone0/trip_point_0_temp:50000
thermal_zone0/trip_point_0_type:active
thermal_zone0/trip_point_1_hyst:5000
thermal_zone0/trip_point_1_temp:60000
thermal_zone0/trip_point_1_type:active
thermal_zone0/trip_point_2_hyst:5000
thermal_zone0/trip_point_2_temp:70000
thermal_zone0/trip_point_2_type:active
thermal_zone0/trip_point_3_hyst:0
thermal_zone0/trip_point_3_temp:120000 <---- this should be last one!
thermal_zone0/trip_point_3_type:critical
thermal_zone0/trip_point_4_hyst:5000
thermal_zone0/trip_point_4_temp:90000
thermal_zone0/trip_point_4_type:passive
thermal_zone0/trip_point_5_hyst:5000
thermal_zone0/trip_point_5_temp:110000
thermal_zone0/trip_point_5_type:passive

After fixing the order in DT, the cpu cooler starts working.

Best regards,
Krzysztof