I can confirm, changing the content of /sys/devices/platform/thinkpad_acpi/hotkey_mask to 0x00ffffff does enable some kind of notification for volume and brightness levels on TP43p. But it is surely not consistent with the overall volume settings.
Here is a test case on how to experience the awkwardness of volume setting with karmic on a TP43p (with or without workaround):
1. Set the volume to 0 with volume down HW button (not the mute button),
2. then adjust volume to maximum through gnome volume applet (up right).
-> You will not hear anything. At least I did not.
The other way round has same effect:
1. Set volume to 0 using gnome applet.
2. adjust volume with HW buttons
-> You will not hear anything. At least I did not
Looks like gnome applet and HW buttons are able to set the maximum volume to 0 without being able to change the volume back to normal vice versa. I guess this is due to the issues Henrique mentioned. HW buttons will set the HW volume to 0, gnome applet will set the software volume to 0.
I can confirm, changing the content of /sys/devices/ platform/ thinkpad_ acpi/hotkey_ mask to 0x00ffffff does enable some kind of notification for volume and brightness levels on TP43p. But it is surely not consistent with the overall volume settings.
Here is a test case on how to experience the awkwardness of volume setting with karmic on a TP43p (with or without workaround):
1. Set the volume to 0 with volume down HW button (not the mute button),
2. then adjust volume to maximum through gnome volume applet (up right).
-> You will not hear anything. At least I did not.
The other way round has same effect:
1. Set volume to 0 using gnome applet.
2. adjust volume with HW buttons
-> You will not hear anything. At least I did not
Looks like gnome applet and HW buttons are able to set the maximum volume to 0 without being able to change the volume back to normal vice versa. I guess this is due to the issues Henrique mentioned. HW buttons will set the HW volume to 0, gnome applet will set the software volume to 0.