xHCI: Kick khubd when USB3 resume really completes. (d93814cf) · Commits · 戴 / test

xHCI roothubs go through slightly different port state machines when either a device initiates a remote wakeup and signals resume, or when the host initiates a resume. According to section 4.19.1.2.13 of the xHCI 1.0 spec, on host-initiated resume, the xHC port state machine automatically goes through the U3Exit state into the U0 state, setting the port link state change (PLC) bit in the process. When a device initiates resume, the xHCI port state machine goes into the "Resume" state and sets the PLC bit. Then the xHCI driver writes U0 into the port link state register to transition the port to U0 from the Resume state. We can't be sure the device is actually in the U0 state until we receive the next port status change event with the PLC bit set. We really don't want khubd to be polling the roothub port status bits until the device is really in U0. Signed-off-by:

Sarah Sharp <sarah.a.sharp@linux.intel.com> Acked-by:

Andiry Xu <andiry.xu@amd.com>

drivers/usb/host/xhci-ring.c

+17 −12

Original line number	Diff line number	Diff line
		@@ -1321,20 +1321,16 @@ static void handle_port_status(struct xhci_hcd *xhci,
		}

		if (DEV_SUPERSPEED(temp)) {
		xhci_dbg(xhci, "resume SS port %d\n", port_id);
		xhci_dbg(xhci, "remote wake SS port %d\n", port_id);
		xhci_test_and_clear_bit(xhci, port_array,
		faked_port_index, PORT_PLC);
		xhci_set_link_state(xhci, port_array, faked_port_index,
		XDEV_U0);
		slot_id = xhci_find_slot_id_by_port(hcd, xhci,
		faked_port_index + 1);
		if (!slot_id) {
		xhci_dbg(xhci, "slot_id is zero\n");
		/* Need to wait until the next link state change
		* indicates the device is actually in U0.
		*/
		bogus_port_status = true;
		goto cleanup;
		}
		xhci_ring_device(xhci, slot_id);
		xhci_dbg(xhci, "resume SS port %d finished\n", port_id);
		/* Clear PORT_PLC */
		xhci_test_and_clear_bit(xhci, port_array,
		faked_port_index, PORT_PLC);
		} else {
		xhci_dbg(xhci, "resume HS port %d\n", port_id);
		bus_state->resume_done[faked_port_index] = jiffies +
		@@ -1345,6 +1341,15 @@ static void handle_port_status(struct xhci_hcd *xhci,
		}
		}

		if ((temp & PORT_PLC) && (temp & PORT_PLS_MASK) == XDEV_U0 &&
		DEV_SUPERSPEED(temp)) {
		xhci_dbg(xhci, "resume SS port %d finished\n", port_id);
		slot_id = xhci_find_slot_id_by_port(hcd, xhci,
		faked_port_index + 1);
		if (slot_id && xhci->devs[slot_id])
		xhci_ring_device(xhci, slot_id);
		}

		if (hcd->speed != HCD_USB3)
		xhci_test_and_clear_bit(xhci, port_array, faked_port_index,
		PORT_PLC);

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