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

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>

diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 1bcf6ee79bc07c6af1fa2911e87dd353836a464d..f331b727dc53e53bf364e2e422914a5809f76b65 100644 (file)
--- 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_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);
@@ -307,7 +307,7 @@ 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]);
        }
@@ -322,8 +322,7 @@ 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);