On Tue, 2011-05-31 at 17:39 -0400, Yu, Fenghua wrote: > > -----Original Message----- > > From: Guenter Roeck [mailto:guenter.roeck@xxxxxxxxxxxx] > > Sent: Tuesday, May 31, 2011 1:29 PM > > To: Jean Delvare > > Cc: LM Sensors; Yu, Fenghua; Carsten Emde > > Subject: Re: [PATCH] hwmon: (coretemp) Relax target > > temperature range check > > > > On Tue, 2011-05-31 at 15:50 -0400, Jean Delvare wrote: > > > The current temperature range check of MSR_IA32_TEMPERATURE_TARGET > > > seems too strict to me, some TjMax values documented in > > > Documentation/hwmon/coretemp wouldn't pass. Relax the check so that > > > all the documented values pass. > > > > > Maybe the reason is that the processors which support reading TjMax via > > the register are all in the 80 .. 120 range. Who knows - unfortunately, > > a simple table describing which processor supports which set of > > registers does not seem to exist, or at least I was unable to find it. > > > > > Signed-off-by: Jean Delvare <khali@xxxxxxxxxxxx> > > > Cc: Carsten Emde <C.Emde@xxxxxxxxx> > > > Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx> > > > > > --- > > > I'm not even sure why we need to check the range. Why would the > > > value read from the MSR be wrong? > > > > If I understand correctly, some processors support the register but not > > the TjMax value in bits 16..23. Here is an exchange about it: > > > > http://www.tomshardware.com/forum/230079-29-intel-tjunction-mean > > I couldn't find " some processors support the register but not > the TjMax value in bits 16..23" in the above site. Not directly, but it says: "Note Tj is not a fixed value and the IA32_TEMPERATURE_TARGET[15:8] value can vary from part to part. Tj is also not software readable." which, as I read it, seems to imply that TjMax is not returned when reading IA32_TEMPERATURE_TARGET on the CPUs mentioned in the article. > Even if there is such hint in the site, I wouldn't use it as a reference for coding. Our coding needs to base on official Intel specifications. > Agreed, if one is available... > I check the SDM about the MSR_TEMPERATURE_TARGET register. My understanding is if the MSR is implemented, its bits 16..23 have the Temperature Target. Otherwise it's a hardware bug. > > There is no spec for the Temperature Target range in SDM (can you find one?). Whatever range we put in coretemp is just speculation. Strictly speaking, we shouldn't have the range check. > I'd be somewhat hesitant to make such a change right away. Maybe we can replace the check with a check against 0 and display a warning (or even an error) if it reads 0. Would that make sense ? Thanks, Guenter _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
