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| author | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2010-10-04 21:46:11 -0700 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2010-10-04 22:36:41 -0700 |
| commit | f6cd378372bff06093d72f978c0150eeed3ea201 (patch) | |
| tree | 352d6d4e720c3e59f47865fb36bb2d78a702d7e6 /drivers/input | |
| parent | d2520a426dc3033c00077e923a553fc6c98c7564 (diff) | |
| download | linux-f6cd378372bff06093d72f978c0150eeed3ea201.tar.gz linux-f6cd378372bff06093d72f978c0150eeed3ea201.tar.bz2 linux-f6cd378372bff06093d72f978c0150eeed3ea201.zip | |
Input: wacom - fix runtime PM related deadlock
When runtime PM is enabled by default for input devices, X hangs in
wacom open:
[<ffffffff814a00ea>] mutex_lock+0x1a/0x40
[<ffffffffa02bc94b>] wacom_resume+0x3b/0x90 [wacom]
[<ffffffff81327a32>] usb_resume_interface+0xd2/0x190
[<ffffffff81327b5d>] usb_resume_both+0x6d/0x110
[<ffffffff81327c24>] usb_runtime_resume+0x24/0x40
[<ffffffff8130a2cf>] __pm_runtime_resume+0x26f/0x450
[<ffffffff8130a23a>] __pm_runtime_resume+0x1da/0x450
[<ffffffff8130a53a>] pm_runtime_resume+0x2a/0x50
[<ffffffff81328176>] usb_autopm_get_interface+0x26/0x60
[<ffffffffa02bc626>] wacom_open+0x36/0x90 [wacom]
wacom_open() takes wacom->lock and calls usb_autopm_get_interface(),
which in turn calls wacom_resume() which tries to acquire the lock
again.
The fix is to call usb_autopm_get_interface() first, before we take
the lock.
Since we do not do usb_autopm_put_interface() until wacom_close()
is called runtime PM is effectively disabled for the driver, however
changing it now would risk regressions so the complete fix will
have to wait till the next merge window.
Reported-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Diffstat (limited to 'drivers/input')
| -rw-r--r-- | drivers/input/tablet/wacom_sys.c | 23 |
1 files changed, 12 insertions, 11 deletions
diff --git a/drivers/input/tablet/wacom_sys.c b/drivers/input/tablet/wacom_sys.c index 42ba3691d908..b35876ee6908 100644 --- a/drivers/input/tablet/wacom_sys.c +++ b/drivers/input/tablet/wacom_sys.c @@ -103,27 +103,26 @@ static void wacom_sys_irq(struct urb *urb) static int wacom_open(struct input_dev *dev) { struct wacom *wacom = input_get_drvdata(dev); + int retval = 0; - mutex_lock(&wacom->lock); - - wacom->irq->dev = wacom->usbdev; - - if (usb_autopm_get_interface(wacom->intf) < 0) { - mutex_unlock(&wacom->lock); + if (usb_autopm_get_interface(wacom->intf) < 0) return -EIO; - } + + mutex_lock(&wacom->lock); if (usb_submit_urb(wacom->irq, GFP_KERNEL)) { - usb_autopm_put_interface(wacom->intf); - mutex_unlock(&wacom->lock); - return -EIO; + retval = -EIO; + goto out; } wacom->open = true; wacom->intf->needs_remote_wakeup = 1; +out: mutex_unlock(&wacom->lock); - return 0; + if (retval) + usb_autopm_put_interface(wacom->intf); + return retval; } static void wacom_close(struct input_dev *dev) @@ -135,6 +134,8 @@ static void wacom_close(struct input_dev *dev) wacom->open = false; wacom->intf->needs_remote_wakeup = 0; mutex_unlock(&wacom->lock); + + usb_autopm_put_interface(wacom->intf); } static int wacom_parse_hid(struct usb_interface *intf, struct hid_descriptor *hid_desc, |