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Subject: Re: Anyone up for ALSA?

Re: Anyone up for ALSA?

From: Dave Hooper <dave_at_beermex.com>
Date: 2005-07-14

One idea - rather than using snd_pcm_open would it be possible to just open
/dev/dsp? (e.g. the same way the irivermidi code works when running on
C - pasted below hopefully)
Just a thought .. all of that snd_pcm_xxx looks more complex than I
suspect it needs to be

void initSound()

{

//OSS Stuff, set the sampling rate, etc: 48000, Mono, 16bit

fd=open("/dev/dsp", O_WRONLY); // | O_NONBLOCK);

int arg, status;

int bit, samp, ch;

arg = 16; // sample size

status = ioctl(fd, SOUND_PCM_WRITE_BITS, &arg);

status = ioctl(fd, SOUND_PCM_READ_BITS, &arg);

bit=arg;

arg = 1; //Number of channels, 1=mono

status = ioctl(fd, SOUND_PCM_WRITE_CHANNELS, &arg);

status = ioctl(fd, SOUND_PCM_READ_CHANNELS, &arg);

ch=arg;

arg = SAMPLE_RATE; //Yeah. sampling rate

status = ioctl(fd, SOUND_PCM_WRITE_RATE, &arg);

status = ioctl(fd, SOUND_PCM_READ_RATE, &arg);

samp=arg;

//Print out what we *actually* got.. not that the program

//pays attention to these values anyway

printf("\nDSP Says:\n%dHz %dCh %dbit", samp, ch, bit);

}

----- Original Message -----
From: "Daniel Stenberg" <daniel@rockbox.org>
To: "Rockbox" <rockbox@cool.haxx.se>
Sent: Wednesday, July 13, 2005 10:56 PM
Subject: Anyone up for ALSA?

> Howdy
>
> I just wrote up a first stab at providing sound in the X11 (on Linux)
> simulator. It doesn't work. :-/
>
> Even though the code is still very basic and crappy, I fell over some
> annoying ALSA initialization issues which aren't really my standard
> neighbourhood issues so I thought I'd cry for help at once...
>
> The problem is this:
>
> I wrote a tiny little stand-alone app first that uses ALSA fine and that
> plays PCM data (and I can hear the glitch in my speakers when it plays
> some random stack data). But when I convert that very same code into a
> function for Rockbox (there's a new PCM playback thread started that will
> deal with all the ALSA/PCM playback stuff) the initial call to
> snd_pcm_open() fails and it prints this informative blurb on stderr:
>
> ALSA lib conf.c:2715:(snd_config_hooks) id of field i is not and integer
> ALSA lib conf.c:3052:(snd_config_update_r) hooks failed, removing
> configuration
> cannot open audio device default (Invalid argument)
>
> Here's this first patch:
>
> http://daniel.haxx.se/rockbox/alsa-1.patch
>
> 1. Beware, it is not even close to fit for commit yet
>
> 2. You need to edit your main Makefile and add "-lasound" along the libs
> to
> link with.
>
> Anyone?
>
> --
> Daniel Stenberg -- http://www.rockbox.org/ -- http://daniel.haxx.se/
> _______________________________________________
> http://cool.haxx.se/mailman/listinfo/rockbox
>

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Received on Thu Jul 14 00:29:16 2005


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