Subject: Re: XMMS (or some other audio player) 'hang' issues with intel8x0
	and dmix plugin [u]
From: "Martin Schlemmer [c]" <azarah@nosferatu.za.org>
Reply-To: Martin Schlemmer <azarah@nosferatu.za.org>
To: Jan Knutar <jk-lkml@sci.fi>
Cc: Christophe Saout <christophe@saout.de>,
       Linux Kernel Mailing Lists <linux-kernel@vger.kernel.org>,
       Takashi Iwai <tiwai@suse.de>, alsa-user@lists.sourceforge.net
In-Reply-To: <200411021340.03164.jk-lkml@sci.fi>
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	 <1099385872.21422.10.camel@leto.cs.pocnet.net>
	 <200411021340.03164.jk-lkml@sci.fi>
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Date: Wed, 03 Nov 2004 03:53:54 +0200
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On Tue, 2004-11-02 at 13:40 +0200, Jan Knutar wrote:
> On Tuesday 02 November 2004 10:57, Christophe Saout wrote:
>=20
> > I've tracked this down to what seems to be a bug in the libalsa dmix
> > code with mmap emulation. If the sound output was stopped for some
> > reason (stream paused or underrun) the library will accept more data
> > until the buffer is full but never restart the output.
>=20
> Strangely, I've observed these kinds of "Hangs" with bmp and mplayer,
> without mmap mode enabled in either. Also using dmix as in the other
> reports here. Could of course be some third application using alsa in
> mmap mode, I suppose.
>=20
> Unfortunately, I have no strace to offer right now as the bug is happenin=
g
> randomly and I haven't been able to find any method by which to reproduce
> it.
>=20
> What's strange is that almost always when it happens, either mplayer or
> beep-media-player will have an extra forked process. As bmp is threaded
> and I shouldn't see more than one bmp in ps aux on NPTL, this seemed a
> bit strange. Strace on the process that looked more recent makes it usual=
ly
> wake up from deep sleep, and then it promptly vanishes after only a few s=
yscalls.
> The strace itself seems to wake it up... After the 'extra' process is gon=
e,
> sound output usually resumes, but not always. Other times strace only rev=
eals
> the app doing nanosleep's and nothing else, and the only solution is to k=
ill
> all apps that might've touched sound.
>=20

I cannot say that I have seen this.  It always just resumes fine if I
click on play again, and I cannot remember it having an extra process.
But then I mostly tried it with mmap enabled (as without it also had
this issue), so I will have a look without mmap, and report if similar
issues happens this side.


Thanks,

--=20
Martin Schlemmer


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