Re: [PATCH v3] thermal: core: Call monitor_thermal_zone() if zone temperature is invalid

[Daniel Lezcano <daniel.lezcano@linaro.org>]

On 15/07/2024 06:45, Eric Biggers wrote:
> Hello,
> 
> On Thu, Jul 04, 2024 at 01:46:26PM +0200, Rafael J. Wysocki wrote:
>> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>
>> Commit 202aa0d4bb53 ("thermal: core: Do not call handle_thermal_trip()
>> if zone temperature is invalid") caused __thermal_zone_device_update()
>> to return early if the current thermal zone temperature was invalid.
>>
>> This was done to avoid running handle_thermal_trip() and governor
>> callbacks in that case which led to confusion.  However, it went too
>> far because monitor_thermal_zone() still needs to be called even when
>> the zone temperature is invalid to ensure that it will be updated
>> eventually in case thermal polling is enabled and the driver has no
>> other means to notify the core of zone temperature changes (for example,
>> it does not register an interrupt handler or ACPI notifier).
>>
>> Also if the .set_trips() zone callback is expected to set up monitoring
>> interrupts for a thermal zone, it needs to be provided with valid
>> boundaries and that can only be done if the zone temperature is known.
>>
>> Accordingly, to ensure that __thermal_zone_device_update() will
>> run again after a failing zone temperature check, make it call
>> monitor_thermal_zone() regardless of whether or not the zone
>> temperature is valid and make the latter schedule a thermal zone
>> temperature update if the zone temperature is invalid even if
>> polling is not enabled for the thermal zone (however, if this
>> continues to fail, give up after some time).
>>
>> Fixes: 202aa0d4bb53 ("thermal: core: Do not call handle_thermal_trip() if zone temperature is invalid")
>> Reported-by: Daniel Lezcano <daniel.lezcano@linaro.org>
>> Link: https://lore.kernel.org/linux-pm/dc1e6cba-352b-4c78-93b5-94dd033fca16@linaro.org
>> Link: https://lore.kernel.org/linux-pm/2764814.mvXUDI8C0e@rjwysocki.net
>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> On v6.10 I'm seeing the following messages spammed to the kernel log endlessly,
> and reverting this commit fixes it.
> 
>      [  156.410567] thermal thermal_zone0: failed to read out thermal zone (-61)
>      [  156.666583] thermal thermal_zone0: failed to read out thermal zone (-61)
>      [  156.922598] thermal thermal_zone0: failed to read out thermal zone (-61)
>      [  157.178613] thermal thermal_zone0: failed to read out thermal zone (-61)
>      [  157.434636] thermal thermal_zone0: failed to read out thermal zone (-61)
>      [  157.690774] thermal thermal_zone0: failed to read out thermal zone (-61)
>      [  157.946659] thermal thermal_zone0: failed to read out thermal zone (-61)
>      [  158.202717] thermal thermal_zone0: failed to read out thermal zone (-61)
>      [  158.458697] thermal thermal_zone0: failed to read out thermal zone (-61)
> 
> /sys/class/thermal/thermal_zone0/type contains "iwlwifi_1".

Does the following change fixes the messages  ?

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/tt.c 
b/drivers/net/wireless/intel/iwlwifi/mvm/tt.c
index 61a4638d1be2..b519db76d402 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/tt.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/tt.c
@@ -622,7 +622,7 @@ static int iwl_mvm_tzone_get_temp(struct 
thermal_zone_device *device,

  	if (!iwl_mvm_firmware_running(mvm) ||
  	    mvm->fwrt.cur_fw_img != IWL_UCODE_REGULAR) {
-		ret = -ENODATA;
+		ret = -EAGAIN;
  		goto out;
  	}


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