[ltp] T60p: thinkpad_acpi automatic module loading

[Henrique de Moraes Holschuh]

On Fri, 30 Mar 2012, Kevin Locke wrote:
> Recently the thinkpad_acpi module stopped loading automatically during
> startup on my T60p (2613-ESU with BIOS "79ETE7WW (2.27 )") running
> Debian testing (udev 175-3.1) and a vanilla kernel.  I thought it was
> a result of upgrading to kernel 3.3, but testing with 3.2 and 3.1 now
> shows the same behavior.  I am certain it was a recent change, but
> can't find the cause.
> 
> I have tried running udev with debug logging and didn't observe
> anything suspicious (although I am unsure what to look for) and I have
> not noticed any other modules which have ceased to load automatically.
> Also, note that thinkpad_acpi loads without issue via modprobe or
> being listed in /etc/modules, the only problem I am having is that it
> has stopped loading automatically.
> 
> Any suggestions for how to debug this, or module auto-loading in
> general, would be greatly appreciated.

Sure, I can help.  First, check whether adding thinkpad_acpi.ko to the
initramfs fixes it.  If it does, report a bug on the distro.  It should
re-attempt autoloading after the initramfs hands over control to
init/systemd/whatever, or it will cause this sort of breakage.

If that doesn't fix it, we will have to assert whether some autoloading
information is missing.

Please run modinfo in the thinkpad_acpi.ko file for your kernel (make *sure*
you get the right file).  I need to know all "alias:" lines reported by
modinfo.

Then, I need to know whether the expected aliases are present in sysfs,
autoloading happens when something in sysfs declares an attribute "modalias"
whose contents are present in the "alias" fields of a module.

In a ThinkPad T43, thinkpad-acpi is autoloaded because this node:
/sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:01/PNP0C09:00/IBM0068:00/modalias

contains: 
acpi:IBM0068:

which will match one of the alias fields that should be in thinkpad_acpi.ko
(alias: acpi*:IBM0068:*) as reported by modinfo.

You should probably have an IBM0068 device somewhere in a T60/p.

If the autoloading information is there, it is likely something wrong with
udev.

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh