From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Date: Sat, 28 Apr 2012 14:43:24 +0000 Subject: Re: [lm-sensors] sensor 3.3.1 and previous do not properly detect/show CPUTIN temperature - maximus Message-Id: <20120428144324.GA23747@ericsson.com> List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: lm-sensors@vger.kernel.org On Sat, Apr 28, 2012 at 04:55:09AM -0400, Jean Delvare wrote: > On Sat, 28 Apr 2012 06:43:53 +0000, P.B. V wrote: > > w83627ehf and nct6775 (Apr 27, 2012) driver modules both show a > > seemingly incorrect value for PECI. I am running a Maximus IV Extreme > > Revision 1.0 motherboard (NCT6776F), with an i5-2550K CPU, on kernel > > 3.3. > >=20 > > The coretemp module and my BIOS reports my idle temperatures at around > > 33-35C, while PECI in Linux reports in at 23-25. It looks to be 10 > > degrees off. Under load it scales with coretemp, always staying 10 > > degrees under the average coretemp values. > >=20 > > Unless I'm not understanding something correctly, PECI should not be > > used and doing so may lead to hardware damage. > >=20 > > coretemp: > > Physical id 0: +36.0 C (high =3D +80.0 C, crit =3D +101.0 C) > > Core 0: +36.0 C (high =3D +80.0 C, crit =3D +101.0 C) > > Core 1: +32.0 C (high =3D +80.0 C, crit =3D +101.0 C) > > Core 2: +34.0 C (high =3D +80.0 C, crit =3D +101.0 C) > > Core 3: +30.0 C (high =3D +80.0 C, crit =3D +101.0 C) > >=20 > > w83627ehf: (nct6775 values are identical) > > PECI Agent 0: +24.0 C >=20 > PECI values are reported (at the hardware level) relative from an > arbitrary maximum. The coretemp driver uses 101=B0C as the maximum, your > results suggests that the w83627ehf and nct6775 drivers use 91=B0C (or > maybe 90=B0C) instead. This isn't going to cause any hardware damage, and > you can even fix the problem in user-space with a compute formula like: >=20 The maximum should be set by the BIOS. On my system (ASUS mainboard) it is correctly set to the critical CPU temperature (99 degrees C in my case). Guess the Maximum board doesn't do that. > chip "nct6776-*" >=20 > compute tempN @ + 10, @ - 10 >=20 > Guenter, is there a way to know what the NCT6776F thinks the maximum > temperature is? Maybe we can read it from registers 0x709 or 0x70A? If > we could present this value as tempN_crit, this would help understand > the difference of absolute temperatures between coretemp and nct6776. >=20 Good idea. I added that to the nct6775 driver (I don't really want to mess with the w83627ehf driver - it is getting too complicated). Output for NCT6776F on my board (i5-2400) is now: PECI Agent 0: +39.0=B0C (high =3D +80.0=B0C, hyst =3D +75.0=B0C) (crit =3D +99.0=B0C) and for NCT6775F (i7-2600): PECI Agent 0: +32.0=B0C (high =3D +80.0=B0C, hyst =3D +75.0=B0C) (crit =3D +98.0=B0C) The attribute is writable. Thanks, Guenter _______________________________________________ lm-sensors mailing list lm-sensors@lm-sensors.org http://lists.lm-sensors.org/mailman/listinfo/lm-sensors