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Commit f370b996 authored by Andiry Xu's avatar Andiry Xu Committed by Sarah Sharp
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xHCI: keep track of ports being resumed and indicate in hub_status_data 



This commit adds a bit-array to xhci bus_state for keeping track of
which ports are undergoing a resume transition. If any of the bits
are set when xhci_hub_status_data() is called, the routine will return
a non-zero value even if no ports have any status changes pending.
This will allow usbcore to handle races between root-hub suspend and
port wakeup.

This patch should be backported to kernels as old as 3.4, that contain
the commit 879d38e6 "USB: fix race
between root-hub suspend and remote wakeup".

Signed-off-by: default avatarAndiry Xu <andiry.xu@amd.com>
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: stable@vger.kernel.org
parent 32445605

drivers/usb/host/xhci-hub.c

+12 −10
Original line number Diff line number Diff line
@@ -558,6 +558,7 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, 
				xhci_dbg(xhci, "Resume USB2 port %d\n",

					wIndex + 1);

				bus_state->resume_done[wIndex] = 0;

				clear_bit(wIndex, &bus_state->resuming_ports);

				xhci_set_link_state(xhci, port_array, wIndex,

							XDEV_U0);

				xhci_dbg(xhci, "set port %d resume\n",
@@ -845,7 +846,12 @@ int xhci_hub_status_data(struct usb_hcd *hcd, char *buf) 
	/* Initial status is no changes */

	retval = (max_ports + 8) / 8;

	memset(buf, 0, retval);

	status = 0;



	/*

	 * Inform the usbcore about resume-in-progress by returning

	 * a non-zero value even if there are no status changes.

	 */

	status = bus_state->resuming_ports;



	mask = PORT_CSC | PORT_PEC | PORT_OCC | PORT_PLC | PORT_WRC;
@@ -885,17 +891,13 @@ int xhci_bus_suspend(struct usb_hcd *hcd) 
	spin_lock_irqsave(&xhci->lock, flags);



	if (hcd->self.root_hub->do_remote_wakeup) {

		port_index = max_ports;

		while (port_index--) {

			if (bus_state->resume_done[port_index] != 0) {

		if (bus_state->resuming_ports) {

			spin_unlock_irqrestore(&xhci->lock, flags);

			xhci_dbg(xhci, "suspend failed because "

						"port %d is resuming\n",

						port_index + 1);

						"a port is resuming\n");

			return -EBUSY;

		}

	}

	}



	port_index = max_ports;

	bus_state->bus_suspended = 0;

drivers/usb/host/xhci-ring.c

+1 −0
Original line number Diff line number Diff line
@@ -1377,6 +1377,7 @@ static void handle_port_status(struct xhci_hcd *xhci, 
			xhci_dbg(xhci, "resume HS port %d\n", port_id);

			bus_state->resume_done[faked_port_index] = jiffies +

				msecs_to_jiffies(20);

			set_bit(faked_port_index, &bus_state->resuming_ports);

			mod_timer(&hcd->rh_timer,

				  bus_state->resume_done[faked_port_index]);

			/* Do the rest in GetPortStatus */

drivers/usb/host/xhci.c

+10 −2
Original line number Diff line number Diff line
@@ -152,7 +152,7 @@ int xhci_reset(struct xhci_hcd *xhci) 
{

	u32 command;

	u32 state;

	int ret;

	int ret, i;



	state = xhci_readl(xhci, &xhci->op_regs->status);

	if ((state & STS_HALT) == 0) {
@@ -175,7 +175,15 @@ int xhci_reset(struct xhci_hcd *xhci) 
	 * xHCI cannot write to any doorbells or operational registers other

	 * than status until the "Controller Not Ready" flag is cleared.

	 */

	return handshake(xhci, &xhci->op_regs->status, STS_CNR, 0, 250 * 1000);

	ret = handshake(xhci, &xhci->op_regs->status, STS_CNR, 0, 250 * 1000);



	for (i = 0; i < 2; ++i) {

		xhci->bus_state[i].port_c_suspend = 0;

		xhci->bus_state[i].suspended_ports = 0;

		xhci->bus_state[i].resuming_ports = 0;

	}



	return ret;

}



#ifdef CONFIG_PCI

drivers/usb/host/xhci.h

+2 −0
Original line number Diff line number Diff line
@@ -1362,6 +1362,8 @@ struct xhci_bus_state { 
	u32			suspended_ports;

	u32			port_remote_wakeup;

	unsigned long		resume_done[USB_MAXCHILDREN];

	/* which ports have started to resume */

	unsigned long		resuming_ports;

};



static inline unsigned int hcd_index(struct usb_hcd *hcd)