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USB: EHCI: Do not rely on PORT_SUSPEND to stop USB resuming in ehci_bus_resume(). 

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>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Wang Zhi 2011-08-17 10:39:31 +08:00 committed by Greg Kroah-Hartman
parent 7e1805844d
commit d0f2fb2500
1 changed files with 3 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/usb/host/ehci-hub.c
View File

@ -343,7 +343,7 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
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);
@ -416,7 +416,7 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
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]);
}
@ -431,8 +431,7 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
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);