[patch 10/31] EHCI: add delay to bus_resume before accessing ports

Greg KH
2007-03-19T21:41:02Z

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-stable review patch. If anyone has any objections, please let us know.

------------------

From: Alan Stern <stern@rowland.harvard.edu>

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@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/usb/host/ehci-hub.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/drivers/usb/host/ehci-hub.c
+++ b/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--) {

--