This is a note to let you know that I've just added the patch titled
USB: EHCI: add delay during suspend to prevent erroneous wakeups
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 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 3e8d6d85adedc59115a564c0a54b36e42087c4d9 Mon Sep 17 00:00:00 2001
From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Date: Thu, 13 Feb 2014 15:49:17 -0500
Subject: USB: EHCI: add delay during suspend to prevent erroneous wakeups
High-speed USB connections revert back to full-speed signalling when
the device goes into suspend. This takes several milliseconds, and
during that time it's not possible to tell reliably whether the device
has been disconnected.
On some platforms, the Wake-On-Disconnect circuitry gets confused
during this intermediate state. It generates a false wakeup signal,
which can prevent the controller from going to sleep.
To avoid this problem, this patch adds a 5-ms delay to the
ehci_bus_suspend() routine if any ports have to switch over to
full-speed signalling. (Actually, the delay was already present for
devices using a particular kind of PHY power management; the patch
merely causes the delay to be used more widely.)
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Peter Chen <Peter.Chen@xxxxxxxxxxxxx>
CC: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/host/ehci-hub.c | 26 ++++++++++++++++++++++----
1 file changed, 22 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 47b858fc50b2..7ae0c4d51741 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -238,6 +238,7 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
int port;
int mask;
int changed;
+ bool fs_idle_delay;
ehci_dbg(ehci, "suspend root hub\n");
@@ -272,6 +273,7 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
ehci->bus_suspended = 0;
ehci->owned_ports = 0;
changed = 0;
+ fs_idle_delay = false;
port = HCS_N_PORTS(ehci->hcs_params);
while (port--) {
u32 __iomem *reg = &ehci->regs->port_status [port];
@@ -300,16 +302,32 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
}
if (t1 != t2) {
+ /*
+ * On some controllers, Wake-On-Disconnect will
+ * generate false wakeup signals until the bus
+ * switches over to full-speed idle. For their
+ * sake, add a delay if we need one.
+ */
+ if ((t2 & PORT_WKDISC_E) &&
+ ehci_port_speed(ehci, t2) ==
+ USB_PORT_STAT_HIGH_SPEED)
+ fs_idle_delay = true;
ehci_writel(ehci, t2, reg);
changed = 1;
}
}
+ spin_unlock_irq(&ehci->lock);
+
+ if ((changed && ehci->has_tdi_phy_lpm) || fs_idle_delay) {
+ /*
+ * Wait for HCD to enter low-power mode or for the bus
+ * to switch to full-speed idle.
+ */
+ usleep_range(5000, 5500);
+ }
if (changed && ehci->has_tdi_phy_lpm) {
- spin_unlock_irq(&ehci->lock);
- msleep(5); /* 5 ms for HCD to enter low-power mode */
spin_lock_irq(&ehci->lock);
-
port = HCS_N_PORTS(ehci->hcs_params);
while (port--) {
u32 __iomem *hostpc_reg = &ehci->regs->hostpc[port];
@@ -322,8 +340,8 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
port, (t3 & HOSTPC_PHCD) ?
"succeeded" : "failed");
}
+ spin_unlock_irq(&ehci->lock);
}
- spin_unlock_irq(&ehci->lock);
/* Apparently some devices need a >= 1-uframe delay here */
if (ehci->bus_suspended)
--
1.8.5.1.163.gd7aced9
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