USB: add missing delay during remote wakeup

This patch (as1330) fixes a bug in khbud's handling of remote
wakeups.  When a device sends a remote-wakeup request, the parent hub
(or the host controller driver, for directly attached devices) begins
the resume sequence and notifies khubd when the sequence finishes.  At
this point the port's SUSPEND feature is automatically turned off.

However the device needs an additional 10-ms resume-recovery time
(TRSMRCY in the USB spec).  Khubd does not wait for this delay if the
SUSPEND feature is off, and as a result some devices fail to behave
properly following a remote wakeup.  This patch adds the missing
delay to the remote-wakeup path.

It also extends the resume-signalling delay used by ehci-hcd and
uhci-hcd from 20 ms (the value in the spec) to 25 ms (the value we use
for non-remote-wakeup resumes).  The extra time appears to help some
devices.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Cc: Rickard Bellini <rickard.bellini@ericsson.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 0cec6caf6e9b26ca385927c6e6b19b67fabbfae2..b9f5fcd713e2752b6e0d5c5f70aa69f861ede03d 100644 (file)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3347,6 +3347,9 @@ static void hub_events(void)
                                        USB_PORT_FEAT_C_SUSPEND);
                                udev = hdev->children[i-1];
                                if (udev) {
+                                       /* TRSMRCY = 10 msec */
+                                       msleep(10);
+
                                        usb_lock_device(udev);
                                        ret = remote_wakeup(hdev->
                                                        children[i-1]);

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 5859522d6edd9f0dde4fc8241d5398b0f4381698..1ec3857f22e65c3cb9474529eea85e62a377b722 100644 (file)
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -787,9 +787,10 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd)
 
                        /* start 20 msec resume signaling from this port,
                         * and make khubd collect PORT_STAT_C_SUSPEND to
-                        * stop that signaling.
+                        * stop that signaling.  Use 5 ms extra for safety,
+                        * like usb_port_resume() does.
                         */
-                       ehci->reset_done [i] = jiffies + msecs_to_jiffies (20);
+                       ehci->reset_done[i] = jiffies + msecs_to_jiffies(25);
                        ehci_dbg (ehci, "port %d remote wakeup\n", i + 1);
                        mod_timer(&hcd->rh_timer, ehci->reset_done[i]);
                }

diff --git a/drivers/usb/host/uhci-hub.c b/drivers/usb/host/uhci-hub.c
index 885b585360b967f23661c015dd8945371f5fa058..8270055848cacd2a8e32379d873b1f624006db71 100644 (file)
--- a/drivers/usb/host/uhci-hub.c
+++ b/drivers/usb/host/uhci-hub.c
@@ -167,7 +167,7 @@ static void uhci_check_ports(struct uhci_hcd *uhci)
                                /* Port received a wakeup request */
                                set_bit(port, &uhci->resuming_ports);
                                uhci->ports_timeout = jiffies +
-                                               msecs_to_jiffies(20);
+                                               msecs_to_jiffies(25);
 
                                /* Make sure we see the port again
                                 * after the resuming period is over. */