[PATCH v6] drm/i915/hwmon: expose fan speed

Andy Shevchenko andriy.shevchenko at linux.intel.com
Tue Aug 20 14:06:39 UTC 2024


On Tue, Aug 20, 2024 at 04:12:46PM +0300, Raag Jadav wrote:
> On Tue, Aug 20, 2024 at 01:23:35PM +0300, Andy Shevchenko wrote:
> > On Tue, Aug 20, 2024 at 11:50:10AM +0530, Raag Jadav wrote:

...

> > > v6: Drop overflow logic (Andy)
> > >     Aesthetic adjustments (Badal)
> > 
> > But it still has an issue with 64-bit division on 32-bit platforms, right?

...

> > > +	/*
> > > +	 * Calculate fan speed in RPM by time averaging two subsequent
> > > +	 * readings in minutes.
> > > +	 * RPM = number of rotations * msecs per minute / time in msecs
> > > +	 */
> > > +	*val = DIV_ROUND_UP(rotations * (MSEC_PER_SEC * 60), time);
> > 
> > ...somewhere here?
> 
> Use div64_u64() instead? Or is there a better alternative?

I don't know the code well to offer anything better. Probably for a starter
you can switch to use DIV_ROUND_UP_ULL().

-- 
With Best Regards,
Andy Shevchenko




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