USB: EHCI: Do not rely on PORT_SUSPEND to stop USB resuming in ehci_b…

…us_resume(). BugLink: http://bugs.launchpad.net/bugs/888042 commit d0f2fb2 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 <[email protected]> Signed-off-by: Alan Stern <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> Signed-off-by: Stefan Bader <[email protected]> Signed-off-by: Tim Gardner <[email protected]> Signed-off-by: Brad Figg <[email protected]>
msiniavine · Nov 30, 2011 · 3817156 · 3817156
1 parent 83b481c
commit 3817156
Showing 1 changed file with 3 additions and 4 deletions.
diff --git 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);