Re: [PATCH] dell-smm-hwmon.c: Additional temperature sensors

["Pali Rohár" <pali.rohar@gmail.com>]

Do you have definite response from Dell support that they are not going
to fix it? Then it is pity :-(

On Thursday 07 February 2019 12:16:06 Michele Sorcinelli wrote:
> As far as I know Dell won't help with fixing the SMM layer, they probably
> changed something starting with firmware version 1.3.0 and they don't
> wanna release information about it.
> 
> https://www.hwinfo.com/forum/Thread-Dell-XPS-15-9570-temperatures-not-named-anymore
> 
> I wonder if something can be done to force the discovery of the sensors in the driver,
> maybe adding a module option to use i8k_get_temp() as probe method as a workaround,
> or maybe just forcing that method for this specific model?
> 
> Let me know your thoughts.
> 
> Thanks,
> Michele.
> 
> On 12/10/18 10:58 AM, Pali Rohár wrote:
> > On Friday 07 December 2018 20:24:49 Guenter Roeck wrote:
> > > Anyway, I would like to get some feedback if this can cause regressions
> > > on systems which don't support that many sensors and maybe report something
> > > completely different if one tries to read the high-numbered sensors.
> > > I seem to recall that there was a reason for checking the type and not just
> > > trying to read sensor values.
> > 
> > There can be also different problem for sensors which are turned off.
> > E.g. on notebooks with switchable graphic cards which have included
> > temperature sensors. When graphic card is turned off, then SMM returns
> > error when asking for temperature value (for obvious reason). But
> > temperature type still returns correct value "this is GPU sensors".
> > 
> > So we cannot replace temp_type check by temp_value check. It introduce
> > race condition between "starting GPU" and initializing dell-smm hwmon.
> > Now linux kernel has support for dynamic turning ON/OFF switchable GPU,
> > so we need to care about these race conditions too.
> > 

-- 
Pali Rohár
pali.rohar@gmail.com