[ltp] Re: T420 Mute LED

Paul Bolle linux-thinkpad@linux-thinkpad.org
Wed, 12 Mar 2014 09:19:53 +0100

On Wed, 2014-03-12 at 08:53 +0200, Marius Gedminas wrote:
> On Sun, Mar 09, 2014 at 09:58:34PM -0700, Peter FP Zhang wrote:
> > T420 Mute/UnMute and its LED handling can not be controlled by event mask or
> > other.
> > Mute button event is reported to BIOS from embedded controller and BIOS
> > processed it by itself to apply the mute setting  and LED. There is no
> > interface to manage them.
> Is that really a good idea?  When I mute the speaker using software, the
> state of the LED doesn't change.  After that, if I use the button, the
> LED shows the opposite of the actual mute state.
> (X220 here, but I'm assuming the same design.)

Also X220 (Fedora 20, Gnome 3.10.y, kernel 3.13.y):
- fiddling with a slider in the top right pop-up-control-area (what's
its current name?): LED does change;
- fiddling with volume buttons (next to the mute button): mute LED turns
off if volume goes up, mute LED turns on _very_ shortly if volume
reaches lowest state (ie, it flashes but doesn't stay on).

(Here I should make a joke about the triviality of this issue, but none
came to mind.)

Paul Bolle