[PATCH 3.2 066/102] ALSA: pcm: fix fifo_size frame calculation

[Ben Hutchings]

3.2.64-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Clemens Ladisch <clemens@xxxxxxxxxx>

commit a9960e6a293e6fc3ed414643bb4e4106272e4d0a upstream.

The calculated frame size was wrong because snd_pcm_format_physical_width()
actually returns the number of bits, not bytes.

Use snd_pcm_format_size() instead, which not only returns bytes, but also
simplifies the calculation.

Fixes: 8bea869c5e56 ("ALSA: PCM midlevel: improve fifo_size handling")
Signed-off-by: Clemens Ladisch <clemens@xxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 sound/core/pcm_lib.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -1692,14 +1692,16 @@ static int snd_pcm_lib_ioctl_fifo_size(s
 {
 	struct snd_pcm_hw_params *params = arg;
 	snd_pcm_format_t format;
-	int channels, width;
+	int channels;
+	ssize_t frame_size;
 
 	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;
+		frame_size = snd_pcm_format_size(format, channels);
+		if (frame_size > 0)
+			params->fifo_size /= (unsigned)frame_size;
 	}
 	return 0;
 }

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