Re: mixer/simple.c bugged? usb-audio

[Takashi Iwai <tiwai@suse.de>]

At Sun, 18 Aug 2002 21:34:52 -0500 (CDT),
Josh Hattery wrote:
> 
> Hi,
> 
> In my previous post I referred to an error message given by xmms (w/
> alsa-xmms plugin).  Since then I set up mplayer and when I started to play
> a divx file the exact same error came up.  Here's the output of both:
> 
> hobbz@graviton:~$ xmms
> xmms: simple.c:1376: snd_mixer_selem_get_playback_volume: Assertion
> `(unsigned int) channel < s->str[0].channels' failed.
> Aborted
> 
> hobbz@graviton:~$ gmplayer -vo xv -ao alsa9
> 
> MPlayer CVS-020817-00:00-2.95.4 (C) 2000-2002 Arpad Gereoffy (see DOCS!)
> 
> CPU: Advanced Micro Devices Athlon 4 PM Palomino/Athlon MP
> Multiprocessor/Athlon XP eXtreme Performance (Family: 6, Stepping: 2)
> CPUflags:  MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 1 SSE2: 0
> Compiled for x86 CPU with extensions: MMX MMX2 3DNow 3DNowEx SSE
> 
> <snip some junk>
> 
> Playing /path/to/somedivx.avi
> Detected AVI file format!
> VIDEO:  [DIV3]  640x360  24bpp  25.00 fps  956.8 kbps (116.8 kbyte/s)
> Clip info:
>  Software: xxx
>  Name: xxx
>  Subject: xxx
>  Artist: xxx
>  Copyright: xxx
>  Comments: xxx
> Detected audio codec: [a52] afm:14 (AC3-liba52)
> Opening audio decoder: [liba52] AC3-liba52
> Using SSE optimized IMDCT transform
> AC3: 2.0 (dolby)  48000 Hz  192.0 kbit/s
> Using MMX optimized resampler
> AUDIO: 48000 Hz, 2 ch, sfmt: 0x10 (2 bps), ratio: 24000->192000 (192.0
> kbit)
> ==========================================================================
> Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
> libavcodec: CPU flags: mmx mmxext 3dnow
> Detected video codec: [ffdivx] vfm:5 (FFmpeg DivX ;-) (MS MPEG-4 v3))
> ==========================================================================
> gmplayer: simple.c:1376: snd_mixer_selem_get_playback_volume: Assertion
> `(unsigned int) channel < s->str[0].channels' failed.
> 
> There are two simple.c files under alsa-lib/. The one this refers to is
> src/mixer/simple.c.  I've noted line 1376 below.
> 
> int snd_mixer_selem_get_playback_volume(snd_mixer_elem_t *elem,
> snd_mixer_selem_channel_id_t channel, long *value)
> {
>         selem_t *s;
>         assert(elem);
>         assert(elem->type == SND_MIXER_ELEM_SIMPLE);
>         s = elem->private_data;
>         assert((unsigned int) channel < s->str[PLAY].channels); /* Line 1376 */
>         assert(s->caps & (CAP_PVOLUME|CAP_GVOLUME));
>         if (s->caps & CAP_PVOLUME_JOIN)
>                 channel = 0;
>         *value = s->str[PLAY].vol[channel];
>         return 0;
> }
> 
> I'm using a Soundblaster Extigy and the snd-usb-audio driver from
> alsa-drivers.
> 
> I just installed the alsa drivers, libs, and utils on my roommate's
> machine with no problem.  The only real difference between our setups is
> that he has an SB Live! Platinum.  So I think the error must originate
> somewhere in the usb code or the way the data is being returned by the
> kernel driver.  Then again, I'm still just a squire when it comes to
> coding.
> 
> Anyone have any insight?

it's involved most likely with the control (mixer) elements.
perhaps exdigy has no "Master" volume element or something like that,
which is referred as default.

IIRC, a similar bug appears when you use xmms-alsa on powermac
driver.

hence, if my guess is correct, it's a bug of alsa-lib, not of the
kernel driver.


Takashi


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