If the high-speed device does not enter full-speed idle after
wakeup on disconnect logic has effected, there will be an
unexpected disconnect wakeup interrupt due to the bus is still SE0.

Signed-off-by: Peter Chen <peter.c...@freescale.com>

Hi Alan,

If you can't met this issue, it may due to your hardware enables
WKDN after detecting full-speed idle or the time between stop
SoF and enable WKDN is more than 3ms (You need to know when
the WKDN has really taken effect).
---
Changes for v3:
- Stop SoF first, then delay 3.5-4ms, enable WKDS at last.

Changes for v2:
- Using usleep_range instead of mdelay

 drivers/usb/host/ehci-hub.c |   22 +++++++++++++++++++++-
 1 files changed, 21 insertions(+), 1 deletions(-)

diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 47b858f..111ac61 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -300,7 +300,27 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
                }
 
                if (t1 != t2) {
-                       ehci_writel(ehci, t2, reg);
+                       /*
+                        * If the high-speed device has not switched
+                        * to full-speed idle before WKDISC_E has taken
+                        * effect, there will be a WKDISC event.
+                        */
+                       if (t2 & PORT_WKDISC_E &&
+                                       (ehci_port_speed(ehci, t2)
+                                        == USB_PORT_STAT_HIGH_SPEED)) {
+                               t2 &= ~PORT_WKDISC_E;
+                               /* Stop SoF first */
+                               ehci_writel(ehci, t2, reg);
+                               spin_unlock_irq(&ehci->lock);
+                               /* Wait for full-speed idle */
+                               usleep_range(3500, 4000);
+                               spin_lock_irq(&ehci->lock);
+                               t2 |= PORT_WKDISC_E;
+                               ehci_writel(ehci, t2, reg);
+                       }
+                       else {
+                               ehci_writel(ehci, t2, reg);
+                       }
                        changed = 1;
                }
        }
-- 
1.7.8


--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to