On 10/29/22 05:33, Marc SCHAEFER wrote:
Hello, I am using the apu2 embedded platform, which uses an amd64 AMD GX-412TC SOC, stepping : 1 microcode : 0x7030105 With Debian bullseye, the power measurement when idle is very big, and wrong (> 80 .. 100 W). We have observed this behaviour on multiple systems. The problem did not occur with Debian buster, does not occur with the temperature sensor, and the power measurement goes back to apparently correct values when the system is no longer idle. It does not seem to be linked to amd64 specific firmwares. The problem lies in the /sys/class/hwmon/hwmon0/power1_average not in the lm-sensors package (direct reading the /sys files gives the same isue). So it appears to be within the kernel: 4.19.0-22-amd64 seems ok and 5.10.0-18-amd64 is not. Funnily, there does not seem to be relevant changes in the specific kernel driver (fam15h_power). Any idea what could lead to this strange behaviour?
A few, but they are all more or less unlikely. - Debian might carry some non-upstream driver patches causing the problem (or fixing it in the older kernel, and the patch was not applied to the new kernel). - Debian installs its own version of the CPU firmware, and the version installed with the newer kernel introduces the problem. Normally the BIOS would update the CPU firmware, but that may not be the case for older systems. - The problem is caused by some change in the kernel outside the fam15h_power driver. I can not imagine what that might be, but it is a possibility. You should be able to check the first two possibilities. For the last one, the only means I could think of would be to bisect between the good and the bad version. Guenter
Thank you for any ideas or pointers. Examples: When bullseye is idle, it's completely wrong (' are from me): cat /sys/class/hwmon/hwmon0/power1_average 94'019'396 When bullseye has 100% CPU used (one core): cat /sys/class/hwmon/hwmon0/power1_average 10'917'309 The only visible change is that hwmon1 and hwmon0 are interchanged: bullseye: fam15h_power-pci-00c4 Adapter: PCI adapter power1: 88.61 W (interval = 0.01 s, crit = 6.00 W)k10temp-pci-00c3Adapter: PCI adapter temp1: +54.5 C (high = +70.0 C) (crit = +105.0 C, h94019396yst = +104.0 C)buster:k10temp-pci-00c3 Adapter: PCI adapter temp1: +59.6°C (high = +70.0°C) (crit = +105.0°C, hyst = +104.0°C)fam15h_power-pci-00c4Adapter: PCI adapter power1: 8.00 W (interval = 0.01 s, crit = 6.00 W)
