Commit 1e2e3fe4 authored by Daniel Girnus's avatar Daniel Girnus Committed by Takashi Iwai

ALSA: usb-audio: avoid setting of sample rate multiple times on bus

Some of userland applications call 'snd_pcm_hw_params()' and
'snd_pcm_hw_prepare()' sequentially, which means 'snd_pcm_hw_prepare()'
is called twice and the second 'snd_pcm_hw_prepare()' is called in
'SNDRV_PCM_STATE_PREPARED' state.

Some devices are not able to manage this and they will stop playback
if the sample rate will be configured several times over USB protocol.

V2: updated Changelog
Signed-off-by: default avatarDaniel Girnus <dgirnus@de.adit-jv.com>
Signed-off-by: default avatarJens Lorenz <jlorenz@de.adit-jv.com>
Signed-off-by: default avatarJiada Wang <jiada_wang@mentor.com>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 4763601a
......@@ -806,17 +806,18 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
if (ret < 0)
goto unlock;
iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
ret = snd_usb_init_sample_rate(subs->stream->chip,
subs->cur_audiofmt->iface,
alts,
subs->cur_audiofmt,
subs->cur_rate);
if (ret < 0)
goto unlock;
if (subs->need_setup_ep) {
iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
ret = snd_usb_init_sample_rate(subs->stream->chip,
subs->cur_audiofmt->iface,
alts,
subs->cur_audiofmt,
subs->cur_rate);
if (ret < 0)
goto unlock;
ret = configure_endpoint(subs);
if (ret < 0)
goto unlock;
......
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