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

[Raag Jadav]

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? 

Raag