[PATCH] spin longer for ehci port reset completion

This makes the EHCI driver spin a bit longer before concluding that the
port reset failed. "Obviously safe."

It allows some devices to enumerate that previously didn't. We've seen
a bunch of these problem reports recently, this will make some go away.

As reported by Michael Zapf <[e-mail]>, some EHCI
controllers seem to take forever to finish port resets and produce
"port N reset error -110" type errors. Spinning a bit longer helps.

Signed-off-by: David Brownell <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/usb/host/ehci-hub.c

···
 			/* force reset to complete */
 			writel (temp & ~PORT_RESET,
 					&ehci->regs->port_status [wIndex]);
+			/* REVISIT:  some hardware needs 550+ usec to clear
+			 * this bit; seems too long to spin routinely...
+			 */
 			retval = handshake (
 					&ehci->regs->port_status [wIndex],
-					PORT_RESET, 0, 500);
+					PORT_RESET, 0, 750);
 			if (retval != 0) {
 				ehci_err (ehci, "port %d reset error %d\n",
 					wIndex + 1, retval);