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Date:      Thu, 18 May 2000 18:40:10 +0200
From:      Udo Erdelhoff <ue@nathan.ruhr.de>
To:        multimedia@FreeBSD.ORG
Subject:   Another datapoint (was Re: Strange problem: fxtv and sound)
Message-ID:  <20000518184009.F19157@nathan.ruhr.de>
In-Reply-To: <20000516200522.A815@ipass.net>; from aa8vb@ipass.net on Tue, May 16, 2000 at 08:05:23PM -0400
References:  <20000508110728.A33101@gruft.de> <3916966C.C5C3EB31@cs.strath.ac.uk> <20000508134336.A33792@gruft.de> <20000508131332.A10497@ipass.net> <20000517012159.A28648@gruft.de> <20000516200522.A815@ipass.net>

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On Tue, May 16, 2000 at 08:05:23PM -0400, Randall Hopper wrote:
> Certainly looks like the sound driver or another app is the culprit.  Fxtv
> is not setting a different value than it got.  Could be an off-by-one
> rounding error in the PCM driver (?)
It certainly looks that way. I'm using -current with an ES1373-based
Soundblaster 64V (relevant details below). The cards works fine (no random
static at mpg123 startup or during heavy system load) but the mixer command
behaves strange:

Just after startup:
ue@nathan$ mixer
Mixer vol      is currently set to  78:78
[...]
ue@nathan$ mixer vol 75
Setting the mixer vol to 75:75.
ue@nathan$ mixer
Mixer vol      is currently set to  78:78
ue@nathan$ mixer vol 74
Setting the mixer vol to 74:74.
ue@nathan$ mixer
Mixer vol      is currently set to  75:75

I've used a small shell script to get "The Big Picture"(tm)
#!/bin/sh
A=0
while [ $A -le 100 ]; do
	mixer vol $A
	mixer
	A=`expr $A + 1`
done

The result is consistent for all mixer devices:
Input Value	Output Value
0		 0
1		 4
2		 4
3		 4
4		 7
5		 7
6		 7
7		10

Further analysis shows that the value "0" is reported only once; the
values 17, 30, 46, 59, 75, 88 and 100 appear four times; all other
possible values appear three times. In other words, 32 different mixer
settings.

Reversing the direction (i.e. counting from 100 to 0) yields the same
results.

And that's the reason for the original poster's problem: fxtv reads the
mixer setting and writes it back. And that's enough to increase the volume
to max with just 32 cycles...

/s/Udo
Config details:

Kernel config: device pcm

Startup messages:
Copyright (c) 1992-2000 The FreeBSD Project.
Copyright (c) 1982, 1986, 1989, 1991, 1993
        The Regents of the University of California. All rights reserved.
FreeBSD 5.0-CURRENT #7: Thu Mar 30 07:45:57 CEST 2000
    root@nathan.ruhr.de:/usr/src/sys/compile/UE
[...]
pcm0: <AudioPCI ES1371> port 0xe000-0xe03f irq 5 at device 9.0 on pci0

cat /dev/sndstat
FreeBSD Audio Driver (newpcm) Mar 30 2000 07:42:07
Installed devices:
pcm0: <AudioPCI ES1371> at io 0xe000 irq 5 (1p/1r channels duplex)


-- 
I'd like to meet the man who invented sex and see what he's working on now.


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