Commit 0200b9f7 authored by Kai-Heng Feng's avatar Kai-Heng Feng Committed by Greg Kroah-Hartman
Browse files

xhci: Wait until link state trainsits to U0 after setting USB_SS_PORT_LS_U0 



Like U3 case, xHCI spec doesn't specify the upper bound of U0 transition
time. The 20ms is not enough for some devices.

Intead of polling PLS or PLC, we can facilitate the port change event to
know that the link transits to U0 is completed.

While at it, also separate U0 and U3 case to make the code cleaner.

[variable rename to u3exit, and skip completion for usb2 ports -Mathias ]
Signed-off-by: default avatarKai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20200312144517.1593-8-mathias.nyman@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent eb002726

drivers/usb/host/xhci-hub.c

+31 −13
Original line number Diff line number Diff line
@@ -1308,7 +1308,33 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, 
					 wIndex, link_state);

				goto error;

			}



			if (link_state == USB_SS_PORT_LS_U0) {

				if ((temp & PORT_PLS_MASK) == XDEV_U0)

					break;



				if (!((temp & PORT_PLS_MASK) == XDEV_U1 ||

				    (temp & PORT_PLS_MASK) == XDEV_U2 ||

				    (temp & PORT_PLS_MASK) == XDEV_U3)) {

					xhci_warn(xhci, "Can only set port %d to U0 from U state\n",

							wIndex);

					goto error;

				}

				reinit_completion(&bus_state->u3exit_done[wIndex]);

				xhci_set_link_state(xhci, ports[wIndex],

						    USB_SS_PORT_LS_U0);

				spin_unlock_irqrestore(&xhci->lock, flags);

				if (!wait_for_completion_timeout(&bus_state->u3exit_done[wIndex],

								 msecs_to_jiffies(100)))

					xhci_dbg(xhci, "missing U0 port change event for port %d\n",

						 wIndex);

				spin_lock_irqsave(&xhci->lock, flags);

				temp = readl(ports[wIndex]->addr);

				break;

			}



			if (link_state == USB_SS_PORT_LS_U3) {

				int retries = 16;

				slot_id = xhci_find_slot_id_by_port(hcd, xhci,

						wIndex + 1);

				if (slot_id) {
@@ -1319,26 +1345,18 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, 
					xhci_stop_device(xhci, slot_id, 1);

					spin_lock_irqsave(&xhci->lock, flags);

				}

			}



			xhci_set_link_state(xhci, ports[wIndex], link_state);



				xhci_set_link_state(xhci, ports[wIndex], USB_SS_PORT_LS_U3);

				spin_unlock_irqrestore(&xhci->lock, flags);

			if (link_state == USB_SS_PORT_LS_U3) {

				int retries = 16;



				while (retries--) {

					usleep_range(4000, 8000);

					temp = readl(ports[wIndex]->addr);

					if ((temp & PORT_PLS_MASK) == XDEV_U3)

						break;

				}

			}

				spin_lock_irqsave(&xhci->lock, flags);



				temp = readl(ports[wIndex]->addr);

			if (link_state == USB_SS_PORT_LS_U3)

				bus_state->suspended_ports |= 1 << wIndex;

			}

			break;

		case USB_PORT_FEAT_POWER:

			/*

drivers/usb/host/xhci-mem.c

+1 −0
Original line number Diff line number Diff line
@@ -2552,6 +2552,7 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags) 
		xhci->usb3_rhub.bus_state.resume_done[i] = 0;

		/* Only the USB 2.0 completions will ever be used. */

		init_completion(&xhci->usb2_rhub.bus_state.rexit_done[i]);

		init_completion(&xhci->usb3_rhub.bus_state.u3exit_done[i]);

	}



	if (scratchpad_alloc(xhci, flags))

drivers/usb/host/xhci-ring.c

+1 −0
Original line number Diff line number Diff line
@@ -1681,6 +1681,7 @@ static void handle_port_status(struct xhci_hcd *xhci, 
	     (portsc & PORT_PLS_MASK) == XDEV_U1 ||

	     (portsc & PORT_PLS_MASK) == XDEV_U2)) {

		xhci_dbg(xhci, "resume SS port %d finished\n", port_id);

		complete(&bus_state->u3exit_done[hcd_portnum]);

		/* We've just brought the device into U0/1/2 through either the

		 * Resume state after a device remote wakeup, or through the

		 * U3Exit state after a host-initiated resume.  If it's a device

drivers/usb/host/xhci.h

+1 −0
Original line number Diff line number Diff line
@@ -1694,6 +1694,7 @@ struct xhci_bus_state { 
	/* Which ports are waiting on RExit to U0 transition. */

	unsigned long		rexit_ports;

	struct completion	rexit_done[USB_MAXCHILDREN];

	struct completion	u3exit_done[USB_MAXCHILDREN];

};

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