ALSA: PCM midlevel: improve fifo_size handling
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>
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index d659995..adc2b0b 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -1524,6 +1524,23 @@
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 @@
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;
}
