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Subject[patch 11/60] USB: fix up EHCI startup synchronization

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

From: David Brownell <>

patch 1cb52658b4f5b10a9e91f8e1c21ca2bcc1b9a3ca in mainline.

A recent patch added software synchronization during EHCI startup,
so ports aren't switched away from the companion controllers after
resets have started. This patch adds a short delay letting hardware
finish that port switching before any new resets begin ... so both
ends of that hardware race window are closed.

Signed-off-by: David Brownell <>
Cc: Dave Miller <>
Cc: Dely Sy <>
Cc: Alan Stern <>
Signed-off-by: Greg Kroah-Hartman <>

drivers/usb/host/ehci-hcd.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -575,12 +575,15 @@ static int ehci_run (struct usb_hcd *hcd
* from the companions to the EHCI controller. If any of the
* companions are in the middle of a port reset at the time, it
* could cause trouble. Write-locking ehci_cf_port_reset_rwsem
- * guarantees that no resets are in progress.
+ * guarantees that no resets are in progress. After we set CF,
+ * a short delay lets the hardware catch up; new resets shouldn't
+ * be started before the port switching actions could complete.
hcd->state = HC_STATE_RUNNING;
ehci_writel(ehci, FLAG_CF, &ehci->regs->configured_flag);
ehci_readl(ehci, &ehci->regs->command); /* unblock posted writes */
+ msleep(5);

temp = HC_VERSION(ehci_readl(ehci, &ehci->caps->hc_capbase));

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