From: Takashi Iwai <[email protected]> 3.12-stable review patch. If anyone has any objections, please let me know.
=============== commit 1ee23fe07ee83a38ecee927e701f762888ada942 upstream. 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 <[email protected]> Signed-off-by: Takashi Iwai <[email protected]> Signed-off-by: Jiri Slaby <[email protected]> --- sound/usb/card.c | 7 +++++-- 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 ca55e033cf9d..bc5795f342a7 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -661,7 +661,7 @@ 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); @@ -673,7 +673,7 @@ 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); } @@ -722,6 +722,8 @@ 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 @@ -737,6 +739,7 @@ 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 caabe9b3af49..58d4ef14ff31 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 */ -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
