At Tue, 30 Oct 2007 21:24:44 +0500, Alexander E. Patrakov wrote:
Trent Piepho wrote:
On Mon, 29 Oct 2007, Alexander E. Patrakov wrote:
Even though mmap seems to be supported in the driver source (judging from .info = SNDRV_PCM_INFO_MMAP | other flags), I could not figure out the parameters that work. Moreover, the driver seems to accept the same hardware parameters without the mmap, and I could not find parameters that the driver accepts for mmap.
I do not think the saa7134-alsa driver supports mmap. The cx88-alsa driver also claimed to support mmap, but it never worked until I fixed it. It's pretty clear that the code in saa7134-alsa was based on the same code as cx88-alsa, so it's likely it has the same bug.
You are right. The patch below (based on your cx88 patch, but I don't really understand it) fixes mmap support in saa7134-alsa for me. Recording via mmap (arecord -M -f S16_LE -c 2 -r 32000 -D hw:1) didn't work at all before, works now, tested for at least 20 minutes (but, unfortunately, with one overrun at least 0.719 ms long).
Signed-off-by: Alexander E. Patrakov patrakov@ums.usu.ru
Looks good to me.
Acked-by: Takashi Iwai tiwai@suse.de
Takashi
--- saa7134-alsa.c 2007-10-12 22:43:44.000000000 +0600 +++ saa7134-alsa.c 2007-10-30 21:01:10.000000000 +0500 @@ -544,8 +544,10 @@ V4L functions, and force ALSA to use that as the DMA area */
substream->runtime->dma_area = dev->dmasound.dma.vmalloc;
- substream->runtime->dma_bytes = dev->dmasound.bufsize;
- substream->runtime->dma_addr = 0;
- return 1;
- return 0;
}
@@ -653,6 +655,17 @@ }
/*
- page callback (needed for mmap)
- */
+static struct page *snd_card_saa7134_page(struct snd_pcm_substream *substream,
unsigned long offset)+{
- void *pageptr = substream->runtime->dma_area + offset;
- return vmalloc_to_page(pageptr);
+}
+/*
- ALSA capture callbacks definition
*/
@@ -665,6 +678,7 @@ .prepare = snd_card_saa7134_capture_prepare, .trigger = snd_card_saa7134_capture_trigger, .pointer = snd_card_saa7134_capture_pointer,
- .page = snd_card_saa7134_page,
};
/*
-- Alexander E. Patrakov