From: Ricardo Neri Date: Thu, 25 Apr 2024 17:13:11 +0000 (-0700) Subject: hwmon: (coretemp) Extend the bitmask to read temperature to 0xff X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f0c344c000d09e38a0240b4a6ccbcd553b18e762;p=linux.git hwmon: (coretemp) Extend the bitmask to read temperature to 0xff The Intel Software Development manual defines the temperature digital readout as the bits [22:16] of the IA32_[PACKAGE]_THERM_STATUS registers. Bit 23 is specified as reserved. In recent processors, however, the temperature digital readout uses bits [23:16]. In those processors, using the bitmask 0x7f would lead to incorrect readings if the temperature deviates from TjMax by more than 127 degrees Celsius. Although not guaranteed, bit 23 is likely to be 0 in processors from a few generations ago. The temperature reading would still be correct in those processors when using a 0xff bitmask. Model-specific provisions can be made for older processors in which bit 23 is not 0 should the need arise. Signed-off-by: Ricardo Neri Link: https://lore.kernel.org/r/20240425171311.19519-4-ricardo.neri-calderon@linux.intel.com Signed-off-by: Guenter Roeck --- diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c index 616bd1a5b8641..1b9203b20d709 100644 --- a/drivers/hwmon/coretemp.c +++ b/drivers/hwmon/coretemp.c @@ -411,7 +411,7 @@ static ssize_t show_temp(struct device *dev, * Return it instead of reporting an error which doesn't * really help at all. */ - tdata->temp = tjmax - ((eax >> 16) & 0x7f) * 1000; + tdata->temp = tjmax - ((eax >> 16) & 0xff) * 1000; tdata->last_updated = jiffies; }