Hi Jean/Guenter, I did not forget about the To Do patch..and was working on it.. Suddenly got to do other things.. Will submit it in a couple of days. Sorry about the delay. Thanks, Durga > -----Original Message----- > From: Guenter Roeck [mailto:guenter.roeck@xxxxxxxxxxxx] > Sent: Wednesday, June 08, 2011 1:06 AM > To: Jean Delvare > Cc: Yu, Fenghua; R, Durgadoss; LM Sensors > Subject: Re: Question about coretemp ttarget > > On Tue, Jun 07, 2011 at 03:27:22PM -0400, Jean Delvare wrote: > > Hi Durgadoss, Fenghua and Guenter, > > > > With commit 199e0de7f5df31a4fc485d4aaaf8a07718252ace (hwmon: (coretemp) > > Merge pkgtemp with coretemp), the following piece of code was added to > > the coretemp driver: > > > > +static void update_ttarget(__u8 cpu_model, struct temp_data *tdata, > > + struct device *dev) > > +{ > > + int err; > > + u32 eax, edx; > > + > > + /* > > + * Initialize ttarget value. Eventually this will be > > + * initialized with the value from MSR_IA32_THERM_INTERRUPT > > + * register. If IA32_TEMPERATURE_TARGET is supported, this > > + * value will be over written below. > > + * To Do: Patch to initialize ttarget from MSR_IA32_THERM_INTERRUPT > > + */ > > + tdata->ttarget = tdata->tjmax - 20000; > > > > I have questions and concerns about this (on top of the fact that this > > side change was not documented and should have been submitted as a > > separate patch, if it is really correct.) > > > > 1* Where does the magic 20°C constant come from? Is this just an > > arbitrary approximation, or is it really correct? > > > > 2* Do all Intel CPUs with DTS really have a target temperature? So far, > > the tempX_max limit (which corresponds to ttarget) was only created > > conditionally, on new CPU models. Older models did not have it. As a > > matter of fact, the documentation file says that the feature is only > > available since Core 2. Please remember that we do NOT want to > > present fake limits to user-space. Any limit exposed to user-space > > should correspond to a real attribute of the CPU (or core.) > > > > 3* Why is the "to do" item not done yet? We have already just made > > significant changes to the coretemp driver, which break user-space > > compatibility to some degree. I don't want to do it again with the > > next kernel version. So if MSR_IA32_THERM_INTERRUPT can be used to > > get a better value for tdata->ttarget, then please let's implement > > it properly right now, for kernel 3.0. > > > > If anyone has comments on this, please speak up. > > > Durgadoss wanted to submit a separate patch to address the "To Do". > I don't know what happened to it. > > Guenter _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
