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Commit d0f2fb25 authored by Wang Zhi's avatar Wang Zhi Committed by Greg Kroah-Hartman
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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: default avatarWang Zhi <zhi.wang@windriver.com>
Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 7e180584

drivers/usb/host/ehci-hub.c

+3 −4
Original line number Diff line number Diff line
@@ -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);