[lm-sensors] [PATCH v3 2/2] hwmon: (coretemp) Add support for thermal threshold attributes

Guenter Roeck guenter.roeck at ericsson.com
Tue Sep 27 20:49:09 CEST 2011


On Tue, 2011-09-27 at 14:41 -0400, Jean Delvare wrote:
> On Tue, 27 Sep 2011 10:13:26 -0700, Guenter Roeck wrote:
> > On Tue, 2011-09-27 at 10:33 -0400, Jean Delvare wrote:
> > > Hi Guenter,
> > > 
> > > Again, sorry for the late review.
> > > 
> > > On Tue, 20 Sep 2011 09:35:03 -0700, Guenter Roeck wrote:
> > > > Add support for T0 and T1 temperature thresholds using the new sysfs ABI
> > > > attributes tempX_thresholdY and tempX_thresholdY_triggered.
> > > >
> > > > This patch is based on commit c814a4c7c4aad795835583344353963a0a673eb0, which
> > > > was reverted. For details on the threshold registers, see IA Manual vol 3A,
> > > > which can be downloaded from here:
> > > >         http://download.intel.com/design/processor/manuals/253668.pdf
> > > >
> > > > Signed-off-by: Guenter Roeck <guenter.roeck at ericsson.com>
> > > > ---
> > > >  Documentation/hwmon/coretemp |    8 ++
> > > >  drivers/hwmon/coretemp.c     |  160 +++++++++++++++++++++++++++++++++++++++---
> > > >  2 files changed, 158 insertions(+), 10 deletions(-)
> > > >
> > > > diff --git a/Documentation/hwmon/coretemp b/Documentation/hwmon/coretemp
> > > > index 84d46c0..3c8dd70 100644
> > > > --- a/Documentation/hwmon/coretemp
> > > > +++ b/Documentation/hwmon/coretemp
> > > > @@ -35,6 +35,14 @@ the Out-Of-Spec bit. Following table summarizes the exported sysfs files:
> > > >  All Sysfs entries are named with their core_id (represented here by 'X').
> > > >  tempX_input   - Core temperature (in millidegrees Celsius).
> > > >  tempX_max     - All cooling devices should be turned on (on Core2).
> > > > +tempX_threshold1 - Reflects value of CPU thermal threshold T0.
> > > > +tempX_threshold1_triggered
> > > > +              - Reflects status of CPU thermal status register bit 6
> > > > +                (THERM_STATUS_THRESHOLD0).
> > > > +tempX_threshold2 - Reflects value of CPU thermal threshold T1.
> > > > +tempX_threshold2_triggered
> > > > +              - Reflects status of CPU thermal status register bit 8
> > > > +                (THERM_STATUS_THRESHOLD1).
> > > 
> > > It's questionable whether we want to map the status bits to _triggered
> > > files. I'd rather map the log bits THERM_LOG_THRESHOLD[01] to
> > > _triggered, because these attributes are direction-neutral, and sticky.
> > > The status bits merely show the result of the real-time comparison
> > > between the current temperature and the threshold value, this is
> > > something user-space can compute by itself.
> > > 
> > > If we really want to expose the status bits, these shouldn't be
> > > considered an alarm (as the thresholds can be used as low or high
> > > temperature limits). _above may be a suitable suffix. But then again
> > > I'm not sure if we really want to expose this.
> >
> > Using THERM_LOG_THRESHOLD is fine with me, and I agree it makes more
> > sense. Only question is what to do after it was read. Auto-reset it, or
> > provide a write function to reset it ?
> 
> Honestly, I Just don't know. With every step, it seems clearer that we
> are designing a new interface but have no idea who will be using it :(
> 
> I bet I would opt for the second option, simply to map to the hardware
> implementation, and also because that's what we do for the chassis
> intrusion detection interface. But I'm not excluding that we change our
> mind once we get actual users of the interface.
> 
Good argument. I'll do it that way.

Thanks,
Guenter






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