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.

-Tino, 2011-10-13