Re: [PATCH] Maestro2 hw volume fix

["Ville Syrjälä" <syrjala@sci.fi>]

On Tue, Feb 17, 2004 at 04:38:12PM +0100, Takashi Iwai wrote:
> At Tue, 17 Feb 2004 08:20:41 +0200,
> Ville Syrjälä wrote:
> > 
> > [1  <text/plain; iso-8859-1 (quoted-printable)>]
> > The attached patch fixes hardware volume buttons on my Dell Inspiron 7000 
> > laptop. The chip is ESS Maestro2 (0x125d:0x1968).
> > 
> > I have no idea if this will break things for someone else. Since the 
> > datasheet didn't help me understand the registers involved I just printed 
> > their contents and came up with the used bits.
> > 
> > All registers had the following values in my tests:
> > mute:     0x99
> > vol down: 0x77
> > vol up:   0xBB
> 
> these values (9, 7, b) are consistent always?

So it would appear. I've tried hitting the buttons in various combinations 
and the values have been consistent.

The only thing that is a bit odd is that after hitting the mute button the 
next vol up/down doesn't generate an interrupt at all. Only the next press 
after that actually works. But that is a hardware issue.

> i'm also not sure whether it's hardware specific...

The device has a subsystem id 0x1028:0x0085 should there be a need to add 
hw specific stuff.



The code in maestro.tar.gz uses GPIO data register 0x60 to check for mute 
button press. That would actually work on my system but I don't see much 
point in checking another register when 0x1C is enough.

The vol up/down test in that code checks for difference between 0x1E and 
0x1F. That would not work on my system because all registers 0x1C-0x1F 
have identical values.

-- 
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/


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