[ltp] How to get volume hotkeys working again on W500?

[Henrique de Moraes Holschuh]

On Sun, 28 Feb 2010, Marc MERLIN wrote:
> I've read the list archives, I know ubuntu did something not much loved
> where they generate X events on the hardware volume keys.

Whether that has any bearing on whatever happens in your system depends on
your ThinkPad model.  The newer ones from Lenovo do *NOT* issue volume
up/down ACPI notifications, they issue volume up/down keypresses and
software has to act on them or the volume won't be changed.

> My W500's hotkey mask comes with:
> gandalf:~# cat /sys/devices/platform/thinkpad_acpi/hotkey_recommended_mask
> 0x038c7fff

AFAIK the W500 doesn't have volume ACPI hotkeys, as it doesn't have a
console volume control anymore (it has just the HDA mixer).  So, it has
volume *keys*, that don't even go through thinkpad-acpi... but thinkpad-acpi
is not informed of that by the firmware so the keys are still there in the
recommended mask.

> Yet, using the mute key still works.

Mute is implemented by the firmware, and may or may not work (or get
reported to thinkpad-acpi) depending on whether the system was given a
OSI(Linux) parameter by the kernel or not.  Whether it happens or not
depends on your kernel command line parameters, and on some hardcoded
blacklists in the kernel source (i.e. kernel version).

> I guess I can live with making this work through X, but any idea what
> changed or what I'm missing?

The hardware lost the extra console (headphone/speakers) volume control, so
it now depends on the HDA mixer to do that.  It *does* have console hardware
mute (independent of the HDA mixer).

-- 
  "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