From d01f87c0ffa96cb44faa78710711eb6e974b891c Mon Sep 17 00:00:00 2001 From: Sarah Sharp Date: Thu, 4 Oct 2012 09:53:43 -0700 Subject: [PATCH] USB: Enable LPM after a failed probe. Before a driver is probed, we want to disable USB 3.0 Link Power Management (LPM), in case the driver needs hub-initiated LPM disabled. After the probe finishes, we want to attempt to re-enable LPM, order to balance the LPM ref count. When a probe fails (such as when libusual doesn't want to bind to a USB 3.0 mass storage device), make sure to balance the LPM ref counts by re-enabling LPM. This patch should be backported to kernels as old as 3.5, that contain the commit 8306095fd2c1100e8244c09bf560f97aca5a311d "USB: Disable USB 3.0 LPM in critical sections." Signed-off-by: Sarah Sharp Cc: stable@vger.kernel.org --- drivers/usb/core/driver.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c index ddd820d25288..6056db7af410 100644 --- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -367,6 +367,10 @@ static int usb_probe_interface(struct device *dev) intf->condition = USB_INTERFACE_UNBOUND; usb_cancel_queued_reset(intf); + /* If the LPM disable succeeded, balance the ref counts. */ + if (!lpm_disable_error) + usb_unlocked_enable_lpm(udev); + /* Unbound interfaces are always runtime-PM-disabled and -suspended */ if (driver->supports_autosuspend) pm_runtime_disable(dev); -- 2.39.5