Hello,

i need to develop for my work an audio recorder application. I have to develop the software on Linux OS (Ubuntu 8.04 with kernel 2.6.23.13), and the motherboard is Gigabyte GA-G41MT-S2P (rev. 1.3) where is installed the integrated audio chipset VIA VT2021 codec.

I upgraded the alsa driver to 1.0.25 version for support of audio chipset VIA VT2021. I downloaded the driver and compiled it with the following option

./configure --with-cards=hda-intel --with-sequencer=yes

and i done some experiments with the following simple application example with alsa lib:

#include <alsa/asoundlib.h>

int main() { int rc; int size; snd_pcm_t *handle; snd_pcm_hw_params_t *params; unsigned int val; int dir; snd_pcm_uframes_t frames; char *buffer;

/* Open PCM device for playback. */ rc = snd_pcm_open(&handle, "default", SND_PCM_STREAM_CAPTURE, 0); if (rc < 0) { fprintf(stderr, "unable to open pcm device: %s\n", snd_strerror(rc)); exit(1); }

/* Allocate a hardware parameters object. */ snd_pcm_hw_params_alloca(&params);

/* Fill it in with default values. */ snd_pcm_hw_params_any(handle, params);

/* Set the desired hardware parameters. */

/* Interleaved mode */ snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);

/* Signed 16-bit little-endian format */ snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_S16_LE);

/* Two channels (stereo) */ snd_pcm_hw_params_set_channels(handle, params, 2);

/* 44100 bits/second sampling rate (CD quality) */ val = 44100; snd_pcm_hw_params_set_rate_near(handle, params, &val, &dir);

/* Set period size to 32 frames. */ frames = 32; snd_pcm_hw_params_set_period_size_near(handle, params, &frames, &dir);

/* Write the parameters to the driver */ rc = snd_pcm_hw_params(handle, params); if (rc < 0) { fprintf(stderr, "unable to set hw parameters: %s\n", snd_strerror(rc)); exit(1); }

/* Use a buffer large enough to hold one period */ snd_pcm_hw_params_get_period_size(params, &frames, &dir); size = frames * 4; /* 2 bytes/sample, 2 channels */ buffer = (char *) malloc(size);

snd_pcm_hw_params_get_period_time(params, &val, &dir);

while (1) { printf ("Capture data\n"); rc = snd_pcm_readi(handle, buffer, size);

if (rc == -EAGAIN) { fprintf(stderr, "EAGAIN occurred\n"); snd_pcm_prepare(handle); } else if (rc == -EPIPE) { fprintf(stderr, "EPIPE occurred\n"); snd_pcm_prepare(handle); } else if (rc == -ESTRPIPE) { fprintf(stderr, "ESTRPIPE occurred\n"); snd_pcm_prepare(handle); } else if (rc > 0) { fprintf(stderr, "read %d ok\n", rc); } else { fprintf(stderr, "error occurred %s\n", snd_strerror(rc)); exit (1); } }

snd_pcm_drain(handle); snd_pcm_close(handle); free(buffer);

return 0; }

Running the example above, I found the following behaviors:

1) Until there is no mic plugged, the application stop on snd_pcm_readi. When mic is plugged, the application starts again. So when i unplug mic the application stops on snd_pcm_readi, when i plug mic the application starts again, and so on. I want to point out that i achieve the same result with a simple stand alone jack.

2) If i reboot my machine with mic plugged, after restart, I run the application but it stop immediately on snd_pcm_readi and I need to unplug/plug the mic to stats again the application.

This behavior seems to me quite strange. Please someone could help me to figure out why this behavior ? Maybe something wrong with my example ? Maybe something wrong with compiling options of the driver or maybe into the drivers itself ?

I tried the same application on a different mainboard with Realtek ALC889 codec, and the applications never stops on snd_pcm_readi (I suppose this is the correct behavior), and run correctly.

Let me know if you need more information about.

Thank to all in advance.

Marco