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Subject[002/107] USB: EHCI: Do not rely on PORT_SUSPEND to stop USB resuming in ehci_bus_resume().
2.6.32-longterm review patch.  If anyone has any objections, please let us know.

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

From: Wang Zhi <zhi.wang@windriver.com>

commit d0f2fb2500b1c5fe4967eb45d8c9bc758d7aef80 upstream.

>From EHCI Spec p.28 HC should clear PORT_SUSPEND when SW clears
PORT_RESUME. In Intel Oaktrail platform, MPH (Multi-Port Host
Controller) core clears PORT_SUSPEND directly when SW sets PORT_RESUME
bit. If we rely on PORT_SUSPEND bit to stop USB resume, we will miss
the action of clearing PORT_RESUME. This will cause unexpected long
resume signal on USB bus.

Signed-off-by: Wang Zhi <zhi.wang@windriver.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/usb/host/ehci-hub.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -243,7 +243,7 @@ static int ehci_bus_resume (struct usb_h
u32 temp;
u32 power_okay;
int i;
- u8 resume_needed = 0;
+ unsigned long resume_needed = 0;

if (time_before (jiffies, ehci->next_statechange))
msleep(5);
@@ -307,7 +307,7 @@ static int ehci_bus_resume (struct usb_h
if (test_bit(i, &ehci->bus_suspended) &&
(temp & PORT_SUSPEND)) {
temp |= PORT_RESUME;
- resume_needed = 1;
+ set_bit(i, &resume_needed);
}
ehci_writel(ehci, temp, &ehci->regs->port_status [i]);
}
@@ -322,8 +322,7 @@ static int ehci_bus_resume (struct usb_h
i = HCS_N_PORTS (ehci->hcs_params);
while (i--) {
temp = ehci_readl(ehci, &ehci->regs->port_status [i]);
- if (test_bit(i, &ehci->bus_suspended) &&
- (temp & PORT_SUSPEND)) {
+ if (test_bit(i, &resume_needed)) {
temp &= ~(PORT_RWC_BITS | PORT_RESUME);
ehci_writel(ehci, temp, &ehci->regs->port_status [i]);
ehci_vdbg (ehci, "resumed port %d\n", i + 1);



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