I've build a card that is registered correctly as far as I can tell.

My hardware is: static struct snd_pcm_hardware my_pcm_hw = { .info = (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_BLOCK_TRANSFER | SNDRV_PCM_INFO_MMAP_VALID), .formats = SNDRV_PCM_FMTBIT_U8, .rates = SNDRV_PCM_RATE_8000, .rate_min = 8000, .rate_max = 8000, .channels_min = 1, .channels_max = 1, .buffer_bytes_max = DMA_LENGTH, .period_bytes_min = 48, .period_bytes_max = 48, .periods_min = 1, .periods_max = 16, };

When I run "arecord -d 2 foo.wav", I get the error message in the subject. Printks show that I get to my_pcm_open, then immediately jump to my_hw_free, my_pcm_close.

I'm in an FPGA embedded system. there are no other cards but mine via arecord -L.

Here's my _init function for the module: struct snd_card *card; struct aaw_device *my_dev; struct snd_pcm *pcm; struct device *dev; int ret;

printk(KERN_ERR "INIT start\n"); snd_card_new(dev,SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1, THIS_MODULE, sizeof(struct my_device), &card); my_dev = card->private_data; my_dev->card = card;

sprintf(card->driver, "my_driver"); sprintf(card->shortname, "My First Audio Driver");

snd_card_set_dev(card,dev);

ret = snd_device_new(card, SNDRV_DEV_LOWLEVEL, my_dev, &dev_ops); if(ret < 0) printk(KERN_ERR "new device err\n"); ret = snd_pcm_new(card, card->driver, 0, 0, 1, &pcm); if(ret < 0) printk(KERN_ERR "new pcm err\n");

snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &my_pcm_ops);

pcm->private_data = my_dev; pcm->info_flags = 0; strcpy(pcm->name, card->shortname);

ret = snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS, snd_dma_continuous_data(GFP_KERNEL), DMA_LENGTH, DMA_LENGTH); if(ret < 0) printk(KERN_ERR "preallocate page err\n");

ret = snd_card_register(card); if (ret < 0) printk(KERN_ERR "error in register snd\n");

Here's my _open function: static int my_pcm_open(struct snd_pcm_substream *ss) { struct my_device *my_dev = ss->private_data;

printk(KERN_ERR "in pcm_open\n"); ss->runtime->hw = my_pcm_hw;

my_dev->substream = ss; ss->runtime->private_data = my_dev; return 0; }

Any help would be most appreciated.

Thanks, Rob