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| author | Takashi Iwai <tiwai@suse.de> | 2014-05-02 18:17:06 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2014-05-02 18:17:06 +0200 |
| commit | 1ee23fe07ee83a38ecee927e701f762888ada942 (patch) | |
| tree | f8af5087956bef2a461410b49584dc3bd2cd988c | |
| parent | 1c53e7253ed8769a00afa0f06777d731dbe1ba6f (diff) | |
| download | linux-stable-1ee23fe07ee83a38ecee927e701f762888ada942.tar.gz linux-stable-1ee23fe07ee83a38ecee927e701f762888ada942.tar.bz2 linux-stable-1ee23fe07ee83a38ecee927e701f762888ada942.zip | |
ALSA: usb-audio: Fix deadlocks at resuming
The recent addition of the USB audio mixer suspend/resume may lead to
deadlocks when the driver tries to call usb_autopm_get_interface()
recursively, since the function tries to sync with the finish of the
other calls. For avoiding it, introduce a flag indicating the resume
operation and avoids the recursive usb_autopm_get_interface() calls
during the resume.
Reported-and-tested-by: Bryan Quigley <gquigs@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
| -rw-r--r-- | sound/usb/card.c | 7 | ||||
| -rw-r--r-- | sound/usb/usbaudio.h | 1 |
2 files changed, 6 insertions, 2 deletions
diff --git a/sound/usb/card.c b/sound/usb/card.c index e769d3977716..c3b5b7dca1c3 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -651,7 +651,7 @@ int snd_usb_autoresume(struct snd_usb_audio *chip) int err = -ENODEV; down_read(&chip->shutdown_rwsem); - if (chip->probing) + if (chip->probing && chip->in_pm) err = 0; else if (!chip->shutdown) err = usb_autopm_get_interface(chip->pm_intf); @@ -663,7 +663,7 @@ int snd_usb_autoresume(struct snd_usb_audio *chip) void snd_usb_autosuspend(struct snd_usb_audio *chip) { down_read(&chip->shutdown_rwsem); - if (!chip->shutdown && !chip->probing) + if (!chip->shutdown && !chip->probing && !chip->in_pm) usb_autopm_put_interface(chip->pm_intf); up_read(&chip->shutdown_rwsem); } @@ -712,6 +712,8 @@ static int __usb_audio_resume(struct usb_interface *intf, bool reset_resume) return 0; if (--chip->num_suspended_intf) return 0; + + chip->in_pm = 1; /* * ALSA leaves material resumption to user space * we just notify and restart the mixers @@ -727,6 +729,7 @@ static int __usb_audio_resume(struct usb_interface *intf, bool reset_resume) chip->autosuspended = 0; err_out: + chip->in_pm = 0; return err; } diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h index 25c4c7e217de..91d0380431b4 100644 --- a/sound/usb/usbaudio.h +++ b/sound/usb/usbaudio.h @@ -40,6 +40,7 @@ struct snd_usb_audio { struct rw_semaphore shutdown_rwsem; unsigned int shutdown:1; unsigned int probing:1; + unsigned int in_pm:1; unsigned int autosuspended:1; unsigned int txfr_quirk:1; /* Subframe boundaries on transfers */ |