[ltp] x41 volume, mute buttons, and acpi

[Paul Fox]

henrique de moraes holschuh wrote:
 > On Wed, 27 Jun 2007, Paul Fox wrote:
 > > marius wrote:
 > >  > On Wed, Jun 27, 2007 at 03:28:27PM -0400, Paul Fox wrote:
 > >  > > they do have a very real effect on output volume, but
 > >  > > no effect on the alsa mixer levels.
 > >  > 
 > >  > They have an effect on alsa mixer levels on my laptop. 
 > >  > Actually, they have a double effect:
 > > 
 > > sigh.  remind me never to buy another thinkpad.  they
 > > definitely don't go to acpid on my X41, and there's no
 > > setting in the bios that lets one control that behavior. 
 > > what idiocy.  :-/
 > 
 > Yes, there is.  And yes, you can partially control it.  And

perhaps you can show me where to control it, then?  it wasn't
in any of the setup screens i looked at.  that's what i mean
by "no setting".  i was hoping for something that said "Let
the OS react to the volume Fn-keys".

 > yes, you need a kernel patch to do it, because I only learned
 > about it about a month ago, so the thinkpad-acpi code that is
 > needed is still being revised.

great!  glad to hear there may be at least a partial solution.

 > 
 > That said:
 > 
 > 1.  There is no reason to do it.  These keys *already* do
 > their function, they control the built-in hardware mixer that
 > drives the speakers and headphone-out, which has nothing to do
 > with the AC97 mixer you see in gnome.

i guess it doesn't really matter to me if they "do their
function", if that function is worthless.  what i want is for
them to do the same thing that every other volume slider in every
other bit of software that i use does.  and they currently don't
do that.

 > 
 > 2.  If you control the AC97 mixer with these keys, you are
 > screwing up your built-in sound (it will work OK for the dock
 > sound output though, as that seems to be done *before* the
 > hardware mixer for the built-in speakers and headphone out, at
 > least on a T43...  and therefore, the keys don't control any
 > hardware that modifies the output levels on the dock sound
 > output).
 > 
 > 3.  The proper way to use these keys is to *ignore* them in
 > the OS, GNOME, KDE, whatever.  They just work.  If you want to

"they just work"?  right now, if i mute the sound with those
keys, i can't unmute it with OS software.  and if i lower the
volume with those keys, i can't raise it (above that level) with
any software control, remotely or locally.  that's pretty far
from "they just work".  if i'm wrong about this, of course i'll
retract the "idiocy" comment. :-)  but until then, it stands.

now, if you're instead laying the blame at the feet of the mixer
folks, and saying that they should be reading something other
standard hardware feature than whatever it is they're reading
now, to get the current volume level, then i'll agree completely. 
somehow i believe this must be possible, given that those keys
probably work seamlessly under windows.  (i've never run windows
on this device.)  but if it takes access to a non-standard piece
of hardware in order to make something as simple as a volume
slider work correctly, then the machine is broken by design.

...
 > > so you get two volume changes stacked on top of one another? 
 > > one from the bios, and one from keybindings?
 > 
 > Yes.  Because nobody should be mapping these keys to something
 > that change volume in any mixers.

no, of course they shouldn't.  that's not why they put little
pictures of speakers on the keys.  ;-)

sorry for my tone, but when i bought this notebook, i did so
because of the great reputation ibm has, or at least had, for
both their hardware and their linux support.  i've been
disappointed.  

[ and let me be clear that i don't think it's the linux
developers that are to blame.  i think the hardware tries quite
hard to make their life difficult.  case in point:  last night
when i came back from work, i put the notebook on its dock, and
plugged in the power supply.  just now, i took it off its dock, and
brought it to the living room.  i logged in at X, then switched
to another console screen.  it was dark.  tried again, with a
different console, tried putting the system to sleep, and waking
it up again, and no matter what, every non-X11 console i tried
was blank.  (i have programs that run on the character consoles,
and they were active, but invisible.)  i had to reboot.  i don't
believe that this was anyone's fault but ibm's. ]

paul
=---------------------
 paul fox, pgf@foxharp.boston.ma.us (arlington, ma, where it's 75.6 degrees)