This is a note to let you know that I've just added the patch titled
USB: Don't use EHCI port sempahore for USB 3.0 hubs.
to the 3.4-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:
usb-don-t-use-ehci-port-sempahore-for-usb-3.0-hubs.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From sarah.a.sharp@xxxxxxxxxxxxxxx Tue Mar 12 15:00:01 2013
From: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
Date: Thu, 7 Mar 2013 16:24:19 -0800
Subject: USB: Don't use EHCI port sempahore for USB 3.0 hubs.
To: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Message-ID: <20130308002419.GA13701@xanatos>
From: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
[This is upstream commit 0fe51aa5eee51db7c7ecd201d42a977ad79c58b6.
It needs to be backported to kernels as old as 3.2, because it fixes the
buggy commit 9dbcaec830cd97f44a0b91b315844e0d7144746b "USB: Handle warm
reset failure on empty port."]
The EHCI host controller needs to prevent EHCI initialization when the
UHCI or OHCI companion controller is in the middle of a port reset. It
uses ehci_cf_port_reset_rwsem to do this. USB 3.0 hubs can't be under
an EHCI host controller, so it makes no sense to down the semaphore for
USB 3.0 hubs. It also makes the warm port reset code more complex.
Don't down ehci_cf_port_reset_rwsem for USB 3.0 hubs.
Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/core/hub.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2330,17 +2330,16 @@ static int hub_port_reset(struct usb_hub
{
int i, status;
- if (!warm) {
- /* Block EHCI CF initialization during the port reset.
- * Some companion controllers don't like it when they mix.
- */
- down_read(&ehci_cf_port_reset_rwsem);
- } else {
- if (!hub_is_superspeed(hub->hdev)) {
+ if (!hub_is_superspeed(hub->hdev)) {
+ if (warm) {
dev_err(hub->intfdev, "only USB3 hub support "
"warm reset\n");
return -EINVAL;
}
+ /* Block EHCI CF initialization during the port reset.
+ * Some companion controllers don't like it when they mix.
+ */
+ down_read(&ehci_cf_port_reset_rwsem);
}
/* Reset the port */
@@ -2378,7 +2377,7 @@ static int hub_port_reset(struct usb_hub
port1);
done:
- if (!warm)
+ if (!hub_is_superspeed(hub->hdev))
up_read(&ehci_cf_port_reset_rwsem);
return status;
Patches currently in stable-queue which might be from sarah.a.sharp@xxxxxxxxxxxxxxx are
queue-3.4/usb-don-t-use-ehci-port-sempahore-for-usb-3.0-hubs.patch
queue-3.4/usb-rip-out-recursive-call-on-warm-port-reset.patch
queue-3.4/usb-prepare-for-refactoring-by-adding-extra-udev-checks.patch
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