This is a note to let you know that I've just added the patch titled
usbcore: enable USB2 LPM if port suspend fails
to the 3.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usbcore-enable-usb2-lpm-if-port-suspend-fails.patch
and it can be found in the queue-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From c3e751e4f4754793bb52bd5ae30e9cc027edbb12 Mon Sep 17 00:00:00 2001
From: Andiry Xu <[email protected]>
Date: Sat, 5 May 2012 00:50:10 +0800
Subject: usbcore: enable USB2 LPM if port suspend fails
From: Andiry Xu <[email protected]>
commit c3e751e4f4754793bb52bd5ae30e9cc027edbb12 upstream.
USB2 LPM is disabled when device begin to suspend and enabled after device
is resumed. That's because USB spec does not define the transition from
U1/U2 state to U3 state.
If usb_port_suspend() fails, usb_port_resume() is never called, and USB2 LPM
is disabled in this situation. Enable USB2 LPM if port suspend fails.
This patch should be backported to kernels as old as 3.2, that contain
the commit 65580b4321eb36f16ae8b5987bfa1bb948fc5112 "xHCI: set USB2
hardware LPM".
Signed-off-by: Andiry Xu <[email protected]>
Signed-off-by: Sarah Sharp <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/usb/core/hub.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2373,6 +2373,10 @@ int usb_port_suspend(struct usb_device *
NULL, 0,
USB_CTRL_SET_TIMEOUT);
+ /* Try to enable USB2 hardware LPM again */
+ if (udev->usb2_hw_lpm_capable == 1)
+ usb_set_usb2_hardware_lpm(udev, 1);
+
/* System sleep transitions should never fail */
if (!(msg.event & PM_EVENT_AUTO))
status = 0;
Patches currently in stable-queue which might be from [email protected] are
queue-3.0/usbcore-enable-usb2-lpm-if-port-suspend-fails.patch
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