From: Alexander E. Patrakov Date: Wed, 31 Oct 2007 14:40:09 +0000 (-0300) Subject: V4L/DVB (6506): saa7134-alsa: Fix mmap support X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=32d111a9f0e6de901667612d1b0c46bbfd5d37cb;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git V4L/DVB (6506): saa7134-alsa: Fix mmap support 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 Acked-by: Takashi Iwai Signed-off-by: Trent Piepho Signed-off-by: Mauro Carvalho Chehab --- diff --git a/drivers/media/video/saa7134/saa7134-alsa.c b/drivers/media/video/saa7134/saa7134-alsa.c index c6f7279669c1..b9c5cf7dc849 100644 --- a/drivers/media/video/saa7134/saa7134-alsa.c +++ b/drivers/media/video/saa7134/saa7134-alsa.c @@ -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, }; /*