LM-Sensors unable to load driver module

Fix - sort of - for LM-Sensors unable to load driver module

In short:

In /etc/default/grub set

GRUB_CMDLINE_LINUX_DEFAULT="quiet acpi_enforce_resources=lax"


then do

# update-grub; reboot


And be prepared for some ACPI trouble.

On many of my systems with recent kernels sensord does no more provide full information:

# sensors
acpitz-virtual-0
Adapter: Virtual device
temp1:       +50.5 C  (crit = +80.0 C)


This is due to buggy ACPI BIOSses which never will get fixed as those are long term out of any support.

The symptoms are:

# sensors-detect
[..]
Driver `w83627hf':
  * ISA bus, address 0x290
    Chip `Winbond W83697HF/F/HG Super IO Sensors' (confidence: 9)
To load everything that is needed, add this to /etc/modules:
#----cut here----
# Chip drivers
w83627hf
#----cut here----


but

# modprobe w83627hf
FATAL: Error inserting w83627hf (/lib/modules/2.6.32-5-686/kernel/drivers/hwmon/w83627hf.ko): Device or resource busy


Usually the power resources and other thermal information should show up in /proc/acpi, but often you just get the CPU information, nothing else. This is because the ACPI part of the BIOS claims the resource, but does not provide appropriate information.

This is a BIOS bug, not a kernel bug. The kernel does the right thing: Protect the ACPI regions against other drivers accessing them, as this can lead to serious problems.

If you know what you are doing - and faulty ACPI BIOSses apparently do not - you can add a commandline option to the Linux kernel to relax this ACPI check:

vi /etc/default/grub


GRUB_CMDLINE_LINUX_DEFAULT="quiet acpi_enforce_resources=lax"


Note that you must add "acpi_enforce_resources=lax" to the DEFAULT commandline. Other settings present there should still be kept. Then do:

update-grub


However you are living in danger then. Having said that you must know, that this was the previous behavior of Linux until this problem was noted and fixed. So there always was ACPI present and you lived in danger, the kernel just did not protect you.

The trick is, to only load this on the DEFAULT commandline, such that it is not present in recovery mode. Hence you still can boot into recovery in case there is some driver conflict with ACPI.

Before

# sensors
acpitz-virtual-0
Adapter: Virtual device
temp1:       +50.5 C  (crit = +80.0 C)


After

# sensors
acpitz-virtual-0
Adapter: Virtual device
temp1:       +48.0 C  (crit = +80.0 C)
w83697hf-isa-0290
Adapter: ISA adapter
in0:         +1.71 V  (min =  +0.13 V, max =  +0.00 V)   ALARM
in2:         +3.20 V  (min =  +0.00 V, max =  +1.15 V)   ALARM
in3:         +3.02 V  (min =  +0.03 V, max =  +2.06 V)   ALARM
in4:         +3.01 V  (min =  +0.00 V, max =  +1.54 V)   ALARM
in5:         +0.67 V  (min =  +0.06 V, max =  +2.05 V)
in6:         +0.91 V  (min =  +1.04 V, max =  +1.02 V)   ALARM
in7:         +3.30 V  (min =  +2.18 V, max =  +0.00 V)   ALARM
in8:         +3.34 V  (min =  +0.19 V, max =  +1.06 V)   ALARM
fan1:       2163 RPM  (min =   -1 RPM, div = 8)  ALARM
fan2:       3013 RPM  (min = 1155 RPM, div = 8)
temp1:       +35.0 C  (high = +16.0 C, hyst = +22.0 C)  ALARM  sensor = thermistor
temp2:       +48.0 C  (high = +80.0 C, hyst = +75.0 C)  sensor = diode
beep_enable:enabled


However as you can see, something still is wrong now. Most limits are really wrong, hence they alarm.

Before they were (however on a different mainboard):

Oct 13 16:41:24 hydra sensord: Chip: w83697hf-isa-0290
Oct 13 16:41:24 hydra sensord: Adapter: ISA adapter
Oct 13 16:41:24 hydra sensord:   in0: +1.74 V (min = +1.57 V, max = +1.73 V) [ALARM]
Oct 13 16:41:24 hydra sensord:   in2: +3.23 V (min = +3.14 V, max = +3.47 V)
Oct 13 16:41:24 hydra sensord:   in3: +3.04 V (min = +2.83 V, max = +3.12 V)
Oct 13 16:41:24 hydra sensord:   in4: +3.04 V (min = +2.85 V, max = +3.47 V)
Oct 13 16:41:24 hydra sensord:   in5: +0.66 V (min = +0.34 V, max = +0.80 V)
Oct 13 16:41:24 hydra sensord:   in6: +0.86 V (min = +0.78 V, max = +0.94 V)
Oct 13 16:41:24 hydra sensord:   in7: +3.28 V (min = +2.83 V, max = +3.12 V) [ALARM]
Oct 13 16:41:24 hydra sensord:   in8: +3.31 V (min = +2.40 V, max = +3.60 V)
Oct 13 16:41:24 hydra sensord:   fan1: 3924 RPM (min = 2343 RPM, div = 8)
Oct 13 16:41:24 hydra sensord:   fan2: 4218 RPM (min = 1155 RPM, div = 8)
Oct 13 16:41:24 hydra sensord:   temp1: 30.0 C (limit = 75.0 C, hysteresis = 55.0 C)
Oct 13 16:41:24 hydra sensord:   temp2: 44.5 C (limit = 80.0 C, hysteresis = 75.0 C)
Oct 13 16:41:24 hydra sensord:   beep_enable: Sound alarm enabled


So apparently at my side the readings seem correct, but the limits not. That is not a problem for me. I need the readings, the rest I can do/fix myself.