This is a note to let you know that I've just added the patch titled
xhci: Don't enable/disable RWE on bus suspend/resume.
to the 3.11-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:
xhci-don-t-enable-disable-rwe-on-bus-suspend-resume.patch
and it can be found in the queue-3.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f217c980ca980e3a645b7485ea5eae9a747f4945 Mon Sep 17 00:00:00 2001
From: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
Date: Mon, 5 Aug 2013 13:36:00 -0700
Subject: xhci: Don't enable/disable RWE on bus suspend/resume.
From: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
commit f217c980ca980e3a645b7485ea5eae9a747f4945 upstream.
The RWE bit of the USB 2.0 PORTPMSC register is supposed to enable
remote wakeup for devices in the lower power link state L1. It has
nothing to do with the device suspend remote wakeup from L2. The RWE
bit is designed to be set once (when USB 2.0 LPM is enabled for the
port) and cleared only when USB 2.0 LPM is disabled for the port.
The xHCI bus suspend method was setting the RWE bit erroneously, and the
bus resume method was clearing it. The xHCI 1.0 specification with
errata up to Aug 12, 2012 says in section 4.23.5.1.1.1 "Hardware
Controlled LPM":
"While Hardware USB2 LPM is enabled, software shall not modify the
HIRDBESL or RWE fields of the USB2 PORTPMSC register..."
If we have previously enabled USB 2.0 LPM for a device, that means when
the USB 2.0 bus is resumed, we violate the xHCI specification by
clearing RWE. It also means that after a bus resume, the host would
think remote wakeup is disabled from L1 for ports with USB 2.0 Link PM
enabled, which is not what we want.
This patch should be backported to kernels as old as 3.2, that
contain the commit 65580b4321eb36f16ae8b5987bfa1bb948fc5112 "xHCI: set
USB2 hardware LPM". That was the first kernel that supported USB 2.0
Link PM.
Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/host/xhci-hub.c | 26 --------------------------
1 file changed, 26 deletions(-)
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -1092,18 +1092,6 @@ int xhci_bus_suspend(struct usb_hcd *hcd
t1 = xhci_port_state_to_neutral(t1);
if (t1 != t2)
xhci_writel(xhci, t2, port_array[port_index]);
-
- if (hcd->speed != HCD_USB3) {
- /* enable remote wake up for USB 2.0 */
- __le32 __iomem *addr;
- u32 tmp;
-
- /* Get the port power control register address. */
- addr = port_array[port_index] + PORTPMSC;
- tmp = xhci_readl(xhci, addr);
- tmp |= PORT_RWE;
- xhci_writel(xhci, tmp, addr);
- }
}
hcd->state = HC_STATE_SUSPENDED;
bus_state->next_statechange = jiffies + msecs_to_jiffies(10);
@@ -1182,20 +1170,6 @@ int xhci_bus_resume(struct usb_hcd *hcd)
xhci_ring_device(xhci, slot_id);
} else
xhci_writel(xhci, temp, port_array[port_index]);
-
- if (hcd->speed != HCD_USB3) {
- /* disable remote wake up for USB 2.0 */
- __le32 __iomem *addr;
- u32 tmp;
-
- /* Add one to the port status register address to get
- * the port power control register address.
- */
- addr = port_array[port_index] + PORTPMSC;
- tmp = xhci_readl(xhci, addr);
- tmp &= ~PORT_RWE;
- xhci_writel(xhci, tmp, addr);
- }
}
(void) xhci_readl(xhci, &xhci->op_regs->command);
Patches currently in stable-queue which might be from sarah.a.sharp@xxxxxxxxxxxxxxx are
queue-3.11/xhci-don-t-enable-disable-rwe-on-bus-suspend-resume.patch
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