Re: Build-in mixer

[Takashi Iwai <tiwai@suse.de>]

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At Wed, 15 Oct 2003 08:40:47 -0400,
Paul Davis wrote:
> 
> >Well, i am not author of this program actually. It is xmms plugin 
> >allowing  to use ALSA for sound output (alsa-xmms-0.9). I only wanted to 
> >modify it, to be able to use dmix. I see, that it is out of my abilities 
> >:-(  and, so i will have to conctact the author of it and ask him to 
> >correct it. It is pitty, because it will take time (if they ever do it). 
> >I thought, that ALSA interface is not dependent on way, how it is opened 
> >(because the same code with "hw:0:0" instead of "default" worked 
> >perfectly) or did not i comprehend anything?. I would like to 
> >understant, why opening "hw:0:0" works and only replacing it by 
> >"default" does not. It seems to mee very dificult for developpers....
> 
> it would have helped enormously if you had stated that you were
> talking about alsa-xmms up front. its a known and important piece of
> code, and one that someone here is much more likely to fix than (sorry
> to say) your own pet project.
> 
> takashi or jaroslav - does using dmix involve any threads? could the
> alsa-xmms plugin be making calls to some xmms error code from a
> non-GUI thread?

it's not related with threads, but it invokes a fork for a server
process (a main control only, doesn't do mixing stuffs).
it looks like there is something wrong with this together with xmms.
i've seen that Xlib got a spurious async.
magically enough, the attached patch seems to fix.

Jaroslav, what is the reason of the second fork?  to daemonize?

hmm, i still got many underruns.  something broken atm...


Takashi

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Index: alsa-lib/src/pcm/pcm_direct.c
===================================================================
RCS file: /suse/tiwai/cvs/alsa/alsa-lib/src/pcm/pcm_direct.c,v
retrieving revision 1.5
diff -u -r1.5 pcm_direct.c
--- alsa-lib/src/pcm/pcm_direct.c	8 Sep 2003 11:23:46 -0000	1.5
+++ alsa-lib/src/pcm/pcm_direct.c	15 Oct 2003 14:03:00 -0000
@@ -313,12 +313,12 @@
 		close(dmix->server_fd);
 		return ret;
 	} else if (ret == 0) {
-		ret = fork();
-		if (ret == 0)
+		//ret = fork();
+		//if (ret == 0)
 			server_job(dmix);
 		exit(EXIT_SUCCESS);
 	} else {
-		waitpid(ret, NULL, 0);
+		//waitpid(ret, NULL, 0);
 	}
 	dmix->server_pid = ret;
 	dmix->server = 1;