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@xxxxxxxxxx>
Looks good to me.
Acked-by: Takashi Iwai <tiwai@xxxxxxx>
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
>
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