USB: EHCI: fix regression during bus resume (2a40f324) · Commits · 戴 / test

This patch (as1663) fixes a regression caused by commit (USB: EHCI: unlink one async QH at a time). In order to avoid keeping multiple QHs in an unusable intermediate state, that commit changed unlink_empty_async() so that it unlinks only one empty QH at a time. However, when the EHCI root hub is suspended, _all_ async QHs need to be unlinked. ehci_bus_suspend() used to do this by calling unlink_empty_async(), but now this only unlinks one of the QHs, not all of them. The symptom is that when the root hub is resumed, USB communications don't work for some period of time. This is because ehci-hcd doesn't realize it needs to restart the async schedule; it assumes that because some QHs are already on the schedule, the schedule must be running. The easiest way to fix the problem is add a new function that unlinks all the async QHs when the root hub is suspended. This patch should be applied to all kernels that have the commit. Signed-off-by:

Alan Stern <stern@rowland.harvard.edu> Reported-and-tested-by:

Adrian Bassett <adrian.bassett@hotmail.co.uk> Cc: stable <stable@vger.kernel.org> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-hcd.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -302,6 +302,7 @@ static void ehci_quiesce (struct ehci_hcd *ehci)

		static void end_unlink_async(struct ehci_hcd *ehci);
		static void unlink_empty_async(struct ehci_hcd *ehci);
		static void unlink_empty_async_suspended(struct ehci_hcd *ehci);
		static void ehci_work(struct ehci_hcd *ehci);
		static void start_unlink_intr(struct ehci_hcd ehci, struct ehci_qh qh);
		static void end_unlink_intr(struct ehci_hcd ehci, struct ehci_qh qh);

drivers/usb/host/ehci-hub.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -328,7 +328,7 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
		ehci->rh_state = EHCI_RH_SUSPENDED;

		end_unlink_async(ehci);
		unlink_empty_async(ehci);
		unlink_empty_async_suspended(ehci);
		ehci_handle_intr_unlinks(ehci);
		end_free_itds(ehci);

drivers/usb/host/ehci-q.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -1316,6 +1316,19 @@ static void unlink_empty_async(struct ehci_hcd *ehci)
		}
		}

		/* The root hub is suspended; unlink all the async QHs */
		static void unlink_empty_async_suspended(struct ehci_hcd *ehci)
		{
		struct ehci_qh *qh;

		while (ehci->async->qh_next.qh) {
		qh = ehci->async->qh_next.qh;
		WARN_ON(!list_empty(&qh->qtd_list));
		single_unlink_async(ehci, qh);
		}
		start_iaa_cycle(ehci, false);
		}

		/* makes sure the async qh will become idle */
		/* caller must own ehci->lock */

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