[Bug 204807] Hardware monitoring sensor nct6798d doesn't work unless acpi_enforce_resources=lax is enabled

bugzilla-daemon
2021-11-05T14:30:12Z

--- Comment #155 from Andy Shevchenko (andy.shevchenko@gmail.com) ---
(In reply to Eugene Shalygin from comment #154)
> (In reply to Olli Asikainen from comment #153)
> > Yeah, it's old and suffers from the same bug, but I reckon supporting this
> > would be a completely different story. Thanks for your answer Eugene and
> > sorry for the noise.
>
> This firmware seem to be using ACPI mutex named \_SB_.PCI0.LPCB.SIO1.MUT0 to
> guard access to the nct chip registers.
>
> I wonder, can we rely on these mutexes, whose names seem to be quite stable,
> as well, instead of the WMI functions? Then accessing nct registers would
> become simpler: lock ACPI mutex if needed, access registers always in the
> regular way, unlock the mutex.

There is a _SEM (semaphore) handling example in the upstream:
https://elixir.bootlin.com/linux/latest/source/drivers/i2c/busses/i2c-designware-baytrail.c
https://elixir.bootlin.com/linux/latest/source/arch/x86/platform/intel/iosf_mbi.c#L275
maybe something similar can be done for ACPI Mutex() object.