On Mon, 10 Feb 2014, Alan Stern wrote:
> On Fri, 7 Feb 2014, Peter Chen wrote:
>
> > If the high-speed device does not enter full-speed idle after
> > wakeup on disconnect logic has effected, there will be an
> > unexpected disconnect wakeup interrupt due to the bus is still SE0.
> >
> > Signed-off-by: Peter Chen <[email protected]>
> >
> > Hi Alan,
> >
> > If you can't met this issue, it may due to your hardware enables
> > WKDN after detecting full-speed idle or the time between stop
> > SoF and enable WKDN is more than 3ms (You need to know when
> > the WKDN has really taken effect).
>
> Yes. However, I don't like the way your patch can increase the total
> time if several ports have to be put into suspend. Consider this patch
> instead.
I decided that patch was more complicated than it needed to be. On
your system, a simple delay is all you need, right? I assume this
means the wakeup signal isn't "sticky". That is, once it has turned
on, it remains on only as long as the wakeup condition is present; it
doesn't stay on even after the wakeup condition goes away.
In your case, the wakeup condition will be present while the bus uses
high-speed terminations, but when the bus switches over to full-speed
idle the wakeup condition will go away. Thus, I assume the wakeup
signal will turn off after a few milliseconds, instead of remaining on
indefinitely.
So tell me what you think of this patch instead.
Alan Stern
Index: usb-3.14/drivers/usb/host/ehci-hub.c
===================================================================
--- usb-3.14.orig/drivers/usb/host/ehci-hub.c
+++ usb-3.14/drivers/usb/host/ehci-hub.c
@@ -238,6 +238,7 @@ static int ehci_bus_suspend (struct usb_
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_
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_
}
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_
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)
--
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