From 1c53e7253ed8769a00afa0f06777d731dbe1ba6f Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Fri, 2 May 2014 18:14:42 +0200 Subject: ALSA: usb-audio: Save mixer status only once at suspend The suspend callback of usb-audio driver may be called multiple times per suspend when multiple USB interfaces are bound to a single sound card instance. In such a case, it's superfluous to save the mixer values multiple times. This patch fixes it by checking the counter. Signed-off-by: Takashi Iwai --- sound/usb/card.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'sound/usb/card.c') diff --git a/sound/usb/card.c b/sound/usb/card.c index 893d5a1afc3c..e769d3977716 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -695,8 +695,9 @@ static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message) chip->autosuspended = 1; } - list_for_each_entry(mixer, &chip->mixer_list, list) - snd_usb_mixer_suspend(mixer); + if (chip->num_suspended_intf == 1) + list_for_each_entry(mixer, &chip->mixer_list, list) + snd_usb_mixer_suspend(mixer); return 0; } -- cgit v1.2.3 From 1ee23fe07ee83a38ecee927e701f762888ada942 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Fri, 2 May 2014 18:17:06 +0200 Subject: 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 Signed-off-by: Takashi Iwai --- sound/usb/card.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'sound/usb/card.c') 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; } -- cgit v1.2.3