From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Date: Sat, 21 Dec 2013 19:55:34 +0000 Subject: Re: [lm-sensors] [PATCH] hwmon: (coretemp) Do not return -EAGAIN for low temperatures Message-Id: <52B5F236.1080606@roeck-us.net> List-Id: References: <1386439557-27341-1-git-send-email-linux@roeck-us.net> In-Reply-To: <1386439557-27341-1-git-send-email-linux@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: lm-sensors@vger.kernel.org On 12/21/2013 10:14 AM, Jean Delvare wrote: > On Fri, 20 Dec 2013 07:53:11 -0800, Guenter Roeck wrote: >> On Sat, Dec 07, 2013 at 10:05:57AM -0800, Guenter Roeck wrote: >>> Some Intel CPUs do not set the 'valid' bit in IA32_THERM_STATUS if the >>> temperature is too low to be measured. This condition will not change u= ntil >>> the CPU is hot enough for its temperature to be measured. Returning an = error >>> in such conditions is not very useful. Drop checking the valid bit and = just >>> return the reported temperature instead. >>> >>> Signed-off-by: Guenter Roeck >>> --- >>> I don't think we ever closed on this. Giving it a shot. >>> >> No feedback. This will go into 3.14 unless there are objections. > > I have no objection, I just don't want this change to go to stable, I > believe it needs a lot of testing on a broad range of hardware before > we can even think of it. > Agreed. > Reviewed-by: Jean Delvare > > On a related note, I think we already noticed that different CPU models > behave differently in low temperature ranges. As an additional data > point, I noticed when staring at sensord graphs that my wife's Core2 > Duo E8400 does clamp at 40=B0C (which is 60=B0C below Tjmax). It never ev= er > reports values below this. Somehow it is a saner implementation than > clearing the valid bit. Too bad we have no way to represent this in > sysfs. Would it make sense to define for example tempX_floor (can't > remember if a better name was ever proposed) so that sensors can report > "< 40=B0C" instead of "40=B0C" in this case? The problem is that I don't > think these clamp values can be read from a register, I'm not even sure > if they are documented, so I'm not sure how useful this would be in > practice... > Question is really if we would ever have a chance to determine the value to report as floor. I suspect the answer is no. Thanks, Guenter _______________________________________________ lm-sensors mailing list lm-sensors@lm-sensors.org http://lists.lm-sensors.org/mailman/listinfo/lm-sensors