[PATCH] EHCI: add delay to bus_resume before accessing ports

[Alan Stern]

This patch (as870) adds a delay to ehci-hcd's bus_resume routine.
Apparently there are controllers and/or BIOSes out there which need
such a delay to get the ports back into their correct state.  This
fixes Bugzilla #8190.

Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>

---

This is for 2.6.20-stable.  Earlier kernels aren't so eager to suspend 
EHCI buses and so don't need this fix.


Index: 2.6.20/drivers/usb/host/ehci-hub.c
===================================================================
--- 2.6.20.orig/drivers/usb/host/ehci-hub.c
+++ 2.6.20/drivers/usb/host/ehci-hub.c
@@ -134,6 +134,10 @@ static int ehci_bus_resume (struct usb_h
 	/* restore CMD_RUN, framelist size, and irq threshold */
 	writel (ehci->command, &ehci->regs->command);
 
+	/* Some controller/firmware combinations need a delay during which
+	 * they set up the port statuses.  See Bugzilla #8190. */
+	mdelay(8);
+
 	/* manually resume the ports we suspended during bus_suspend() */
 	i = HCS_N_PORTS (ehci->hcs_params);
 	while (i--) {

-
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