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ALSA: usb-audio: Fix broken resume due to UAC3 power state

Message ID 20230612132818.29486-1-tiwai@suse.de (mailing list archive)
State Accepted
Commit 8ba61c9f6c9bdfbf9d197b0282641d24ae909778
Headers show
Series ALSA: usb-audio: Fix broken resume due to UAC3 power state | expand

Commit Message

Takashi Iwai June 12, 2023, 1:28 p.m. UTC 
As reported in the bugzilla below, the PM resume of a UAC3 device may
fail due to the incomplete power state change, stuck at D1.  The
reason is that the driver expects the full D0 power state change only
at hw_params, while the normal PCM resume procedure doesn't call
hw_params.

For fixing the bug, we add the same power state update to D0 at the
prepare callback, which is certainly called by the resume procedure.

Note that, with this change, the power state change in the hw_params
becomes almost redundant, since snd_usb_hw_params() doesn't touch the
parameters (at least it tires so).  But dropping it is still a bit
risky (e.g. we have the media-driver binding), so I leave the D0 power
state change in snd_usb_hw_params() as is for now.

Fixes: a0a4959eb4e9 ("ALSA: usb-audio: Operate UAC3 Power Domains in PCM callbacks")
Cc: <stable@vger.kernel.org>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217539
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/usb/pcm.c | 4 ++++
 1 file changed, 4 insertions(+)
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Patch

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index eec5232f9fb2..08bf535ed163 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -650,6 +650,10 @@  static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
 		goto unlock;
 	}
 
+	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
+	if (ret < 0)
+		goto unlock;
+
  again:
 	if (subs->sync_endpoint) {
 		ret = snd_usb_endpoint_prepare(chip, subs->sync_endpoint);