This is a note to let you know that I've just added the patch titled
USB: don't ignore suspend errors for root hubs
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also will be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From cd4376e23a59a2adf3084cb5f4a523e6d5fd4e49 Mon Sep 17 00:00:00 2001
From: Alan Stern <[email protected]>
Date: Wed, 28 Mar 2012 15:56:17 -0400
Subject: USB: don't ignore suspend errors for root hubs
This patch (as1532) fixes a mistake in the USB suspend code. When the
system is going to sleep, we should ignore errors in powering down USB
devices, because they don't really matter. The devices will go to low
power anyway when the entire USB bus gets suspended (except for
SuperSpeed devices; maybe they will need special treatment later).
However we should not ignore errors in suspending root hubs,
especially if the error indicates that the suspend raced with a wakeup
request. Doing so might leave the bus powered on while the system was
supposed to be asleep, or it might cause the suspend of the root hub's
parent controller device to fail, or it might cause a wakeup request
to be ignored.
The patch fixes the problem by ignoring errors only when the device in
question is not a root hub.
Signed-off-by: Alan Stern <[email protected]>
Reported-by: Chen Peter <[email protected]>
CC: <[email protected]>
Tested-by: Chen Peter <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/usb/core/driver.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index f8e2d6d..9a56635 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1189,8 +1189,13 @@ static int usb_suspend_both(struct usb_device *udev,
pm_message_t msg)
if (status == 0) {
status = usb_suspend_device(udev, msg);
- /* Again, ignore errors during system sleep transitions */
- if (!PMSG_IS_AUTO(msg))
+ /*
+ * Ignore errors from non-root-hub devices during
+ * system sleep transitions. For the most part,
+ * these devices should go to low power anyway when
+ * the entire bus is suspended.
+ */
+ if (udev->parent && !PMSG_IS_AUTO(msg))
status = 0;
}
--
1.7.10
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