Since 2.6.35 kernel , coretemp driver assumes TjMax for Core2Duo T5800 (and maybe others) , but as stated on intel.ark , and official coretemp documentation TjMax for this model is 85 C.
Is this a regression? Was the coretemp driver in kernel 2.6.34 and earlier properly setting TjMax to 85°C for your Core2 Duo T5800 CPU?
Yes , TjMax was set with 85 degrees , and since 2.6.35 kernels , it assumes it as 100 C. At first i thought that for some reason CPU got hotter with newer kernels , but then i read the documentation and saw that TjMax is incorectly set. Should i put an attachment with pre-.35 krenels , and >= .35 ?
Here is clearly stated that TjMax for C2Duo T800 is 85°C. http://www.mjmwired.net/kernel/Documentation/hwmon/coretemp http://ark.intel.com/Product.aspx?id=35581
(In reply to comment #3) > Here is clearly stated that TjMax for C2Duo T800 is 85°C. > http://www.mjmwired.net/kernel/Documentation/hwmon/coretemp > http://ark.intel.com/Product.aspx?id=35581 C2Duo T5800
TjMax detection was updated in 2.6.35 to use the MSR_IA32_TEMPERATURE_TARGET register if available. If the register is not available, the code no longer adjusts TjMax unconditionally, but only for CPU families 0x17 (Core 2 Extreme and some Xeons)and 0x1c (Atom). Core 2 Duo is family 0xe or 0xf, thus TjMax is no longer adjusted for those CPUs. Please try the driver at http://roeck-us.net/linux/drivers/coretemp/ and let me know if it fixes your problem. Note that it is based on the latest driver code in 3.0-rc1, so it might not compile on versions older than 2.6.35, and the output will be a bit different as well.
(In reply to comment #5) > TjMax detection was updated in 2.6.35 to use the MSR_IA32_TEMPERATURE_TARGET > register if available. If the register is not available, the code no longer > adjusts TjMax unconditionally, but only for CPU families 0x17 (Core 2 Extreme > and some Xeons)and 0x1c (Atom). Core 2 Duo is family 0xe or 0xf, thus TjMax > is > no longer adjusted for those CPUs. > > Please try the driver at http://roeck-us.net/linux/drivers/coretemp/ and let > me > know if it fixes your problem. Note that it is based on the latest driver > code > in 3.0-rc1, so it might not compile on versions older than 2.6.35, and the > output will be a bit different as well. This works as it should! Core 0: +58.0°C (high = +85.0°C, crit = +85.0°C) Compiled against 2.6.38.7. Thanks!
Will this go into mainline?
At some point yes. I'll have to make sure that the fix doesn't break something else, though - maybe there was a reason for excluding Core 2 Duo CPUs from temperature adjustment.
A patch referencing this bug report has been merged in v3.0-rc2: commit 4f5f71a7abe329bdad81ee6a8e4545054a7cc30a Author: Guenter Roeck <guenter.roeck@ericsson.com> Date: Tue May 31 06:54:21 2011 -0700 hwmon: (coretemp) Fix TjMax detection for older CPUs
Patch should hopefully make its way into 2.6.35 and 2.6.39. Its final version (or, rather, the resulting driver) is also available at the link provided earlier.