USB: add missing delay during remote wakeup (49d0f078) · Commits · 戴 / test

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>

drivers/usb/core/hub.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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]);

drivers/usb/host/ehci-hcd.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -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]);
		}

drivers/usb/host/uhci-hub.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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. */

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