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V4L/DVB (6506): saa7134-alsa: Fix mmap support

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Trent Piepho wrote:
> 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>
Acked-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
This commit is contained in:
Alexander E. Patrakov 2007-10-31 11:40:09 -03:00 committed by Mauro Carvalho Chehab
parent f21daa41d1
commit 32d111a9f0
1 changed files with 15 additions and 1 deletions
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16
drivers/media/video/saa7134/saa7134-alsa.c
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@ -543,8 +543,10 @@ static int snd_card_saa7134_hw_params(struct snd_pcm_substream * substream,
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;
}
@ -651,6 +653,17 @@ static int snd_card_saa7134_capture_open(struct snd_pcm_substream * substream)
return 0;
}
/*
* 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
*/
@ -664,6 +677,7 @@ static struct snd_pcm_ops snd_card_saa7134_capture_ops = {
.prepare = snd_card_saa7134_capture_prepare,
.trigger = snd_card_saa7134_capture_trigger,
.pointer = snd_card_saa7134_capture_pointer,
.page = snd_card_saa7134_page,
};
/*