ALSA: pcm: fix fifo_size frame calculation

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@ladisch.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 9acc77e..0032278 100644 (file)
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -1782,14 +1782,16 @@ static int snd_pcm_lib_ioctl_fifo_size(struct snd_pcm_substream *substream,
 {
        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;
 }