[PATCH v1] drm/i915/hwmon: expose fan speed

[Riana Tauro]

On 7/23/2024 3:53 PM, Raag Jadav wrote:
> On Mon, Jul 22, 2024 at 04:20:51PM +0530, Riana Tauro wrote:
>> Hi Raag
>>
>> On 7/12/2024 5:53 PM, Raag Jadav wrote:
>>> Add hwmon support for fan1_input attribute, which will expose fan speed
>>> in RPM. With this in place we can monitor fan speed using lm-sensors tool.
>>>
>>> $ sensors
>>> i915-pci-0300
>>> Adapter: PCI adapter
>>> in0:         653.00 mV
>>> fan1:        3833 RPM
>>> power1:           N/A  (max =  43.00 W)
>>> energy1:      32.02 kJ
>>>
>> Add fixes tag with the bug link
> 
> We still need temperature information to mark it as a fix.
> 
>>> @@ -771,6 +834,14 @@ hwm_get_preregistration_info(struct drm_i915_private *i915)
>>>    		for_each_gt(gt, i915, i)
>>>    			hwm_energy(&hwmon->ddat_gt[i], &energy);
>>>    	}
>>> +
>>> +	if (i915_mmio_reg_valid(hwmon->rg.fan_speed)) {
>>> +		/* Take initial readings and use it while calculating actual fan speed. */
>>> +		with_intel_runtime_pm(uncore->rpm, wakeref)
>>> +			ddat->fi.reg_val_prev = intel_uncore_read(ddat->uncore,
>>> +								  hwmon->rg.fan_speed);
>>> +		ddat->fi.time_prev = jiffies_to_msecs(jiffies);
>>> +	}
>>
>> Move this under with_intel_runtime_pm condition used above.
> 
> We don't need to fiddle with runtime_pm if it is INVALID_MMIO_REG.
> Doesn't this make more sense? Or am I missing something?

Wouldn't it be better to move under the condition where
energy prev value changes are. Just an ordering change so up to you.

Thanks,
Riana

> 
> Raag