Wrong handling of volume buttons on IBM Thinkpad notebooks
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
gnome-control-center |
Won't Fix
|
Unknown
|
|||
acpi-support (Ubuntu) |
Fix Released
|
Undecided
|
Unassigned | ||
gnome-control-center (Ubuntu) |
Invalid
|
Low
|
Ubuntu Desktop Bugs | ||
gnome-settings-daemon (Ubuntu) |
Invalid
|
Low
|
Ubuntu Desktop Bugs | ||
hotkey-setup (Ubuntu) |
New
|
Undecided
|
Unassigned |
Bug Description
Most IBM / Lenovo Thinkpads have hardware volume control with apropriate buttons above the keyboard (volume up, down and mute). Gnome in Ubuntu is configured in such a way, that the keypresses are trapped (this is correct), apropriate volume window is displayed (correct) and Gnome volume control is modified. Last step is actually wrong - the keys in Thinkpads control the volume hardware directly, so every keypress turns the volume up/down regardless of sound card settings (in Ubuntu case - this would be Alsa mixer). Current behaviour results in volume being changed twice - for example if I press the volume up button, I get volume reduction via Gnome sound mixer plus volume reduction via hardware control. Effectively this creates an exponential (and not linear as it should be) volume change. In short - it is very difficult to control volume, especially relatively quiet sounds, with volume keys only.
The "patch" solution is to decouple Gnome mixer from hardware buttons. Of course it could be done manually, by deleting apropriate key actions in System-
I tested this on T21, T42 and Thinkpad 600. I guess only some R series notebooks (R31 etc.) would not be affected, as these do not have hardware mixer.
Steps to reproduce:
1. Press hardware volume key (eg. volume up) on a Thinkpad
2. Observe the volume change - it is changed in hardware mixer (correct) and in Gnome volume control (incorrect)
Changed in gnome-control-center: | |
status: | Unknown → Fix Released |
Changed in gnome-control-center: | |
status: | Fix Released → New |
Changed in gnome-control-center: | |
status: | New → Won't Fix |
I can confirm this. I also find the behaviour iritating. As an additional bug I have the problem that the volume bar decreases faster than it should and increases slower than it should.
That means that if you decrease the volume the bar is at 0% even when there is still sound to hear. Press "Volume Down" again a few times and the sound is *really* muted.
Same thing about "Volume Up". When the voule is at its loudest the bar is only at 50%.
I have an IBM ThinkPad R40 2722-CDG but I could also reproduce this problem on an R50 of a friend of mine.