[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 <Michael.Zapf@uni-kassel.de>, 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 <dbrownell@users.sourceforge.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 429330bc..d7b4f79 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -439,9 +439,12 @@
/* 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);