From alsa-devel-owner@alsa.jcu.cz  Fri Jul 17 00:01:32 1998
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Date: Fri, 17 Jul 1998 00:01:20 +0200 (MET DST)
From: Jaroslav Kysela <perex@jcu.cz>
To: Jim Pick <jim@jimpick.com>
cc: alsa-devel@alsa.jcu.cz
Subject: Re: Hardware mute on the SB16
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On 16 Jul 1998, Jim Pick wrote:

> Hi,
> 
> I installed ALSA (from the Debian packages) yesterday because I was
> looking for a solution to a problem I was having.  I've got a headset
> that I wanted to use for telephony, but in order to record at a decent
> volume for recording on the MIC input, I've got to bump up the level
> pretty high.
> 
> I've got a really old AWE32 (ie. SB16 based).
> 
> Unfortunately, the SB16 mixer uses the same register for the MIC on
> both the input and output mixers.  So if the output mixer has the MIC
> switched on, and I have the level set high (so I can record), I get
> blasted in the ear whenever I talk, giving me an earache.
> 
> The Linux/OSS driver (in 2.0.34) doesn't seem to have the API to
> toggle off the MIC input to the output mixer (which goes to my
> earphone) - it can only reduce the volume to zero, which means I can't
> record.  so I took a look at ALSA.
> 
> The ALSA 0.1.4 driver seemed to have the API, but when I muted, I
> could record on the input mixer.  Checking into it further, I see
> that it only had software muting implemented.  So I made a patch to
> do hardware muting, which I'll attach at the end.
> 
> Please tell me if it's good enough to apply.  I'm using it here, and
> it does the job for me.  The only reason I can see not to apply it is
> if you really intend for "mute" to work on the input mixer (for
> recording) as well (which I don't want).

Good work, but above problem is already solved (nearly same code) in
ftp://alsa.jcu.cz/pub/driver/test/sb16 and code will be in 0.2.0-pre2
prelease of driver. It will be pretty if you can confirm, that code in
test directory works for you, too.

					Jaroslav

-----
Jaroslav Kysela <perex@jcu.cz>
Academic Computer Centre, University of South Bohemia
Branisovska 31, C. Budejovice, CZ-370 05 Czech Republic


