USB: EHCI: Do not rely on PORT_SUSPEND to stop USB resuming in ehci_bus_resume().
Wang Zhi [Wed, 17 Aug 2011 02:39:31 +0000 (10:39 +0800)]
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>

drivers/usb/host/ehci-hub.c

index e051b30..4c32cb1 100644 (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);