* Re: [PATCH v3] arm64: dts: qcom: x1e78100-thinkpad-t14s: Add thermal zones for PMICs
2026-10-14 19:35 [PATCH v3] arm64: dts: qcom: x1e78100-thinkpad-t14s: Add thermal zones for PMICs Daniel Lezcano
@ 2026-10-14 19:36 ` johannes.goede
2026-10-14 19:47 ` sashiko-bot
2026-10-16 9:56 ` Stephan Gerhold
2 siblings, 0 replies; 5+ messages in thread
From: johannes.goede @ 2026-10-14 19:36 UTC (permalink / raw)
To: Daniel Lezcano, andersson, konradybcio
Cc: robh, krzk+dt, conor+dt, stephan.gerhold, linux-arm-msm,
devicetree, linux-kernel
Hi,
On 14-Oct-26 21:35, Daniel Lezcano wrote:
> Add thermal zones for the ThinkPad T14s and describe the board
> temperature sensors exposed through the PMK8550 VADC.
>
> Add a passive thermal zone for the keyboard area, which is the main
> thermal constraint under sustained load. The EC reports a thermal alert
> at 57.85°C, so use this value as the passive trip point and allow the
> thermal framework to throttle all CPUs and the GPU when the threshold is
> reached. Use a 1000 m°C hysteresis and a 500 ms passive polling interval.
>
> An earlier approach used staged CPU cluster throttling in an attempt to
> start thermal mitigation before reaching the target temperature. Testing
> did not show a significant improvement compared to throttling all CPUs at
> the EC thermal alert threshold. It also introduced a latency imbalance
> between the different CPU clusters, which could negatively affect
> workloads depending on where tasks are scheduled.
>
> A more optimal solution would require a significantly more complex,
> system-wide approach, accounting for the workload distribution and the
> available power and thermal headroom across the CPU clusters and other
> devices. Such an approach would also require kernel mechanisms which are
> not currently available. Keep the thermal policy simple here and use a
> single passive trip, which at least ensures that the system is actively
> mitigated before reaching temperatures that could ultimately lead to a
> thermal shutdown.
>
> The mitigation temperature is derived from the platform behaviour when
> using the balanced power profile available under Windows. A separate
> change will adjust this trip point dynamically according to events
> reported by the embedded controller. Name the trip
> "keyboard-ec-alert" so that the EC driver can identify the corresponding
> trip point in the device tree.
>
> Also add a 73°C critical trip to shut the system down if the keyboard
> temperature reaches an unsafe level.
>
> Add a thermal zone for the back cover with a 73°C critical shutdown
> trip.
>
> Describe the SoC, SMB, SDX, east and west board temperature sensors as
> monitoring-only thermal zones.
>
> Thermal camera measurements were also used to compare the reported
> temperatures with the physical temperature of the chassis. The measured
> values appear to primarily represent temperatures inside the enclosure
> rather than the user-contact surface temperature. No unsafe external
> surface temperature was observed during these tests, although this should
> not be considered a substitute for formal platform thermal qualification.
>
> Finally, enable ADC thermal monitoring on the corresponding PMK8550 VADC
> channels used by these thermal zones.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@oss.qualcomm.com>
Thanks, patch looks good to me:
Reviewed-by: Hans de Goede <johannes.goede@oss.qualcomm.com>
Regards,
Hans
> ---
> .../qcom/x1e78100-lenovo-thinkpad-t14s.dtsi | 105 ++++++++++++++++++
> 1 file changed, 105 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> index 75ad74bcb042..2d0a434d2248 100644
> --- a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> +++ b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> @@ -502,6 +502,81 @@ platform {
> };
> };
> };
> +
> + thermal-zones {
> + backcover-thermal {
> + critical-action = "shutdown";
> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX1_THM_100K_PU(1)>;
> +
> + trips {
> + backcover-critical {
> + temperature = <73000>;
> + hysteresis = <1000>;
> + type = "critical";
> + };
> + };
> + };
> +
> + east-thermal {
> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX4_THM_100K_PU(1)>;
> + };
> +
> + keyboard-thermal {
> + critical-action = "shutdown";
> + polling-delay-passive = <500>;
> +
> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX2_GPIO_100K_PU(1)>;
> +
> + trips {
> + keyboard_ec_alert: keyboard-ec-alert {
> + temperature = <57850>;
> + hysteresis = <1000>;
> + type = "passive";
> + };
> +
> + keyboard-critical {
> + temperature = <73000>;
> + hysteresis = <1000>;
> + type = "critical";
> + };
> + };
> +
> + cooling-maps {
> + map0 {
> + trip = <&keyboard_ec_alert>;
> + cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu2 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu3 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu4 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu5 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu6 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu7 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu8 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu9 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu10 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu11 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&gpu THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> + };
> + };
> + };
> +
> + sdx-thermal {
> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX3_THM_100K_PU(1)>;
> + };
> +
> + smb-thermal {
> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX2_THM_100K_PU(1)>;
> + };
> +
> + soc-thermal {
> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX1_GPIO_100K_PU(1)>;
> + };
> +
> + west-thermal {
> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX5_THM_100K_PU(1)>;
> + };
> + };
> };
>
> &apps_rsc {
> @@ -1285,6 +1360,36 @@ usb0_pwr_1p15_reg_en: usb0-pwr-1p15-reg-en-state {
> };
> };
>
> +&pmk8550_vadc {
> + channel@144 {
> + qcom,adc-tm;
> + };
> +
> + channel@145 {
> + qcom,adc-tm;
> + };
> +
> + channel@146 {
> + qcom,adc-tm;
> + };
> +
> + channel@147 {
> + qcom,adc-tm;
> + };
> +
> + channel@148 {
> + qcom,adc-tm;
> + };
> +
> + channel@14a {
> + qcom,adc-tm;
> + };
> +
> + channel@14b {
> + qcom,adc-tm;
> + };
> +};
> +
> &qupv3_0 {
> status = "okay";
> };
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v3] arm64: dts: qcom: x1e78100-thinkpad-t14s: Add thermal zones for PMICs
2026-10-14 19:35 [PATCH v3] arm64: dts: qcom: x1e78100-thinkpad-t14s: Add thermal zones for PMICs Daniel Lezcano
2026-10-14 19:36 ` johannes.goede
@ 2026-10-14 19:47 ` sashiko-bot
2026-10-14 19:52 ` Daniel Lezcano
2026-10-16 9:56 ` Stephan Gerhold
2 siblings, 1 reply; 5+ messages in thread
From: sashiko-bot @ 2026-10-14 19:47 UTC (permalink / raw)
To: Daniel Lezcano; +Cc: devicetree, robh, conor+dt
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] dts: missing #thermal-sensor-cells causes thermal zone registration failure
--
commit fd5ef96fe4a4a5f82c85c0157e689c00a5a97d30
Author: Daniel Lezcano <daniel.lezcano@oss.qualcomm.com>
arm64: dts: qcom: x1e78100-thinkpad-t14s: Add thermal zones for PMICs
Add thermal zones for the ThinkPad T14s and describe the board
temperature sensors exposed through the PMK8550 VADC.
> diff --git a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> index 0bee2a3d6e7a9..9586421553442 100644
> --- a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> +++ b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> @@ -502,6 +502,81 @@ platform {
> };
> };
> };
> +
> + thermal-zones {
> + backcover-thermal {
> + critical-action = "shutdown";
> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX1_THM_100K_PU(1)>;
[Severity: High]
Does this setup cause thermal zone registration to fail at boot?
During boot, the thermal framework resolves the thermal-sensors phandle using
of_parse_phandle_with_args(), which expects the target node to have a
#thermal-sensor-cells property.
Since the target pmk8550_vadc node lacks the #thermal-sensor-cells property,
will the device tree parser return -EINVAL, causing thermal_of_zone_register()
to abort registration for all these newly added thermal zones?
[ ... ]
> @@ -1285,6 +1360,36 @@ usb0_pwr_1p15_reg_en: usb0-pwr-1p15-reg-en-state {
> };
> };
>
> +&pmk8550_vadc {
> + channel@144 {
> + qcom,adc-tm;
> + };
[Severity: High]
Should this override block include `#thermal-sensor-cells = <1>;`?
Adding the missing property here would allow the thermal framework to
successfully parse and register the thermal zones.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261014193524.5590-1-daniel.lezcano@oss.qualcomm.com?part=1
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v3] arm64: dts: qcom: x1e78100-thinkpad-t14s: Add thermal zones for PMICs
2026-10-14 19:47 ` sashiko-bot
@ 2026-10-14 19:52 ` Daniel Lezcano
0 siblings, 0 replies; 5+ messages in thread
From: Daniel Lezcano @ 2026-10-14 19:52 UTC (permalink / raw)
To: sashiko-reviews; +Cc: devicetree, robh, conor+dt
On 10/14/26 21:47, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [High] dts: missing #thermal-sensor-cells causes thermal zone registration failure
> --
>
> commit fd5ef96fe4a4a5f82c85c0157e689c00a5a97d30
> Author: Daniel Lezcano <daniel.lezcano@oss.qualcomm.com>
>
> arm64: dts: qcom: x1e78100-thinkpad-t14s: Add thermal zones for PMICs
>
> Add thermal zones for the ThinkPad T14s and describe the board
> temperature sensors exposed through the PMK8550 VADC.
>
>> diff --git a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
>> index 0bee2a3d6e7a9..9586421553442 100644
>> --- a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
>> +++ b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
>> @@ -502,6 +502,81 @@ platform {
>> };
>> };
>> };
>> +
>> + thermal-zones {
>> + backcover-thermal {
>> + critical-action = "shutdown";
>> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX1_THM_100K_PU(1)>;
>
> [Severity: High]
> Does this setup cause thermal zone registration to fail at boot?
>
> During boot, the thermal framework resolves the thermal-sensors phandle using
> of_parse_phandle_with_args(), which expects the target node to have a
> #thermal-sensor-cells property.
>
> Since the target pmk8550_vadc node lacks the #thermal-sensor-cells property,
> will the device tree parser return -EINVAL, causing thermal_of_zone_register()
> to abort registration for all these newly added thermal zones?
>
> [ ... ]
>
>> @@ -1285,6 +1360,36 @@ usb0_pwr_1p15_reg_en: usb0-pwr-1p15-reg-en-state {
>> };
>> };
>>
>> +&pmk8550_vadc {
>> + channel@144 {
>> + qcom,adc-tm;
>> + };
>
> [Severity: High]
> Should this override block include `#thermal-sensor-cells = <1>;`?
>
> Adding the missing property here would allow the thermal framework to
> successfully parse and register the thermal zones.
False positive:
https://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux.git/tree/arch/arm64/boot/dts/qcom/hamoa-pmics.dtsi?h=for-next#n291
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3] arm64: dts: qcom: x1e78100-thinkpad-t14s: Add thermal zones for PMICs
2026-10-14 19:35 [PATCH v3] arm64: dts: qcom: x1e78100-thinkpad-t14s: Add thermal zones for PMICs Daniel Lezcano
2026-10-14 19:36 ` johannes.goede
2026-10-14 19:47 ` sashiko-bot
@ 2026-10-16 9:56 ` Stephan Gerhold
2 siblings, 0 replies; 5+ messages in thread
From: Stephan Gerhold @ 2026-10-16 9:56 UTC (permalink / raw)
To: Daniel Lezcano
Cc: andersson, konradybcio, robh, krzk+dt, johannes.goede, conor+dt,
linux-arm-msm, devicetree, linux-kernel, Mark Pearson
On Wed, Oct 14, 2026 at 09:35:24PM +0200, Daniel Lezcano wrote:
> Add thermal zones for the ThinkPad T14s and describe the board
> temperature sensors exposed through the PMK8550 VADC.
>
> Add a passive thermal zone for the keyboard area, which is the main
> thermal constraint under sustained load. The EC reports a thermal alert
> at 57.85°C, so use this value as the passive trip point and allow the
> thermal framework to throttle all CPUs and the GPU when the threshold is
> reached. Use a 1000 m°C hysteresis and a 500 ms passive polling interval.
>
> An earlier approach used staged CPU cluster throttling in an attempt to
> start thermal mitigation before reaching the target temperature. Testing
> did not show a significant improvement compared to throttling all CPUs at
> the EC thermal alert threshold. It also introduced a latency imbalance
> between the different CPU clusters, which could negatively affect
> workloads depending on where tasks are scheduled.
>
> A more optimal solution would require a significantly more complex,
> system-wide approach, accounting for the workload distribution and the
> available power and thermal headroom across the CPU clusters and other
> devices. Such an approach would also require kernel mechanisms which are
> not currently available. Keep the thermal policy simple here and use a
> single passive trip, which at least ensures that the system is actively
> mitigated before reaching temperatures that could ultimately lead to a
> thermal shutdown.
>
> The mitigation temperature is derived from the platform behaviour when
> using the balanced power profile available under Windows. A separate
> change will adjust this trip point dynamically according to events
> reported by the embedded controller. Name the trip
> "keyboard-ec-alert" so that the EC driver can identify the corresponding
> trip point in the device tree.
>
> Also add a 73°C critical trip to shut the system down if the keyboard
> temperature reaches an unsafe level.
>
> Add a thermal zone for the back cover with a 73°C critical shutdown
> trip.
>
> Describe the SoC, SMB, SDX, east and west board temperature sensors as
> monitoring-only thermal zones.
>
> Thermal camera measurements were also used to compare the reported
> temperatures with the physical temperature of the chassis. The measured
> values appear to primarily represent temperatures inside the enclosure
> rather than the user-contact surface temperature. No unsafe external
> surface temperature was observed during these tests, although this should
> not be considered a substitute for formal platform thermal qualification.
>
Thanks to Mark, I was able to get some info on the location/purpose of
the thermal sensors in the T14s. As you noted already here, the sensors
are primarily focused on specific components inside the enclosure rather
than user-contact surface temperatures. Below I added some suggestions
for more accurate names for the thermal zones. Perhaps that helps to
optimize the thermal control further.
> Finally, enable ADC thermal monitoring on the corresponding PMK8550 VADC
> channels used by these thermal zones.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@oss.qualcomm.com>
> ---
> .../qcom/x1e78100-lenovo-thinkpad-t14s.dtsi | 105 ++++++++++++++++++
> 1 file changed, 105 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> index 75ad74bcb042..2d0a434d2248 100644
> --- a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> +++ b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> @@ -502,6 +502,81 @@ platform {
> };
> };
> };
> +
> + thermal-zones {
> + backcover-thermal {
> + critical-action = "shutdown";
> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX1_THM_100K_PU(1)>;
dram-thermal or memory-thermal (or maybe keyboard-thermal if you want to
give it a user-surface name, although that purpose seems to be
secondary).
Next to DRAM memory, on the top part of the mainboard, facing upwards to
the keyboard. Unrelated to the backcover.
> +
> + trips {
> + backcover-critical {
> + temperature = <73000>;
> + hysteresis = <1000>;
> + type = "critical";
> + };
Is this critical temperature is appropriate for the DRAM temperature?
Windows seems to have 115°C here as critical trip point which is maybe a
bit too high.
> + };
> + };
> +
> + east-thermal {
> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX4_THM_100K_PU(1)>;
gpu-pmic-thermal (next to GPU-related PMICs close to the SoC)
> + };
> +
> + keyboard-thermal {
> + critical-action = "shutdown";
> + polling-delay-passive = <500>;
> +
> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX2_GPIO_100K_PU(1)>;
fan-thermal or heatpipe-thermal (or maybe backcover-thermal if you want
to give it a user-surface name, although that purpose seems to be
secondary).
Next to fan/heat pipe, on the bottom part of the mainboard, facing
downwards to the back cover. Unrelated to the keyboard.
> +
> + trips {
> + keyboard_ec_alert: keyboard-ec-alert {
> + temperature = <57850>;
> + hysteresis = <1000>;
> + type = "passive";
> + };
> +
> + keyboard-critical {
> + temperature = <73000>;
> + hysteresis = <1000>;
> + type = "critical";
> + };
> + };
> +
> + cooling-maps {
> + map0 {
> + trip = <&keyboard_ec_alert>;
> + cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu2 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu3 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu4 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu5 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu6 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu7 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu8 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu9 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu10 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu11 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&gpu THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> + };
> + };
> + };
> +
> + sdx-thermal {
> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX3_THM_100K_PU(1)>;
wwan-thermal
> + };
> +
> + smb-thermal {
> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX2_THM_100K_PU(1)>;
charger-thermal
> + };
> +
> + soc-thermal {
> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX1_GPIO_100K_PU(1)>;
cpu-pmic-thermal (next to CPU-related PMICs close to SoC)
> + };
> +
> + west-thermal {
> + thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX5_THM_100K_PU(1)>;
typec-thermal or usbc-thermal
Next to USB-C ports, bottom part of mainboard, facing towards the back
cover.
> + };
> + };
There is also ssd-thermal @ SYS_THERM7
thermal-sensors = <&pmk8550_adc_tm ADC5_GEN3_AMUX6_THM_100K_PU(1)>;
as I mentioned before.
Windows uses the EC sensors for throttling, although given that we don't
have interrupt support for the EC yet, I think it is fine to initially
use the PMIC sensors.
Thanks,
Stephan
^ permalink raw reply [flat|nested] 5+ messages in thread