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ALSA: PCM midlevel: improve fifo_size handling

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Move the fifo_size assignment to hw->ioctl callback to allow lowlevel
drivers overwrite the default behaviour.

fifo_size is in frames not bytes as specified in asound.h and alsa-lib's
documentation, but most hardware have fixed byte based FIFOs. Introduce
internal SNDRV_PCM_INFO_FIFO_IN_FRAMES.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Jaroslav Kysela
2009-04-27 09:44:40 +02:00
committed by Takashi Iwai
parent e93721a702
commit 8bea869c5e
4 changed files with 33 additions and 3 deletions
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19
sound/core/pcm_lib.c
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@@ -1524,6 +1524,23 @@ static int snd_pcm_lib_ioctl_channel_info(struct snd_pcm_substream *substream,
return 0;
}
static int snd_pcm_lib_ioctl_fifo_size(struct snd_pcm_substream *substream,
void *arg)
{
struct snd_pcm_hw_params *params = arg;
snd_pcm_format_t format;
int channels, width;
params->fifo_size = substream->runtime->hw.fifo_size;
if (!(substream->runtime->hw.info & SNDRV_PCM_INFO_FIFO_IN_FRAMES)) {
format = params_format(params);
channels = params_channels(params);
width = snd_pcm_format_physical_width(format);
params->fifo_size /= width * channels;
}
return 0;
}
/**
* snd_pcm_lib_ioctl - a generic PCM ioctl callback
* @substream: the pcm substream instance
@@ -1545,6 +1562,8 @@ int snd_pcm_lib_ioctl(struct snd_pcm_substream *substream,
return snd_pcm_lib_ioctl_reset(substream, arg);
case SNDRV_PCM_IOCTL1_CHANNEL_INFO:
return snd_pcm_lib_ioctl_channel_info(substream, arg);
case SNDRV_PCM_IOCTL1_FIFO_SIZE:
return snd_pcm_lib_ioctl_fifo_size(substream, arg);
}
return -ENXIO;
}