The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2f31a67f01a8beb22cae754c53522cb61a005750 Mon Sep 17 00:00:00 2001

From: Mathias Nyman mathias.nyman@linux.intel.com Date: Thu, 15 Nov 2018 11:38:41 +0200 Subject: [PATCH] usb: xhci: Prevent bus suspend if a port connect change or polling state is detected

USB3 roothub might autosuspend before a plugged USB3 device is detected, causing USB3 device enumeration failure.

USB3 devices don't show up as connected and enabled until USB3 link trainig completes. On a fast booting platform with a slow USB3 link training the link might reach the connected enabled state just as the bus is suspending.

If this device is discovered first time by the xhci_bus_suspend() routine it will be put to U3 suspended state like the other ports which failed to suspend earlier.

The hub thread will notice the connect change and resume the bus, moving the port back to U0

This U0 -> U3 -> U0 transition right after being connected seems to be too much for some devices, causing them to first go to SS.Inactive state, and finally end up stuck in a polling state with reset asserted

Fix this by failing the bus suspend if a port has a connect change or is in a polling state in xhci_bus_suspend().

Don't do any port changes until all ports are checked, buffer all port changes and only write them in the end if suspend can proceed

Cc: stable@vger.kernel.org Signed-off-by: Mathias Nyman mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c index da98a11244e2..94aca1b5ac8a 100644 --- a/drivers/usb/host/xhci-hub.c +++ b/drivers/usb/host/xhci-hub.c @@ -1474,15 +1474,18 @@ int xhci_bus_suspend(struct usb_hcd *hcd) unsigned long flags; struct xhci_hub *rhub; struct xhci_port **ports; + u32 portsc_buf[USB_MAXCHILDREN]; + bool wake_enabled;

rhub = xhci_get_rhub(hcd); ports = rhub->ports; max_ports = rhub->num_ports; bus_state = &xhci->bus_state[hcd_index(hcd)]; + wake_enabled = hcd->self.root_hub->do_remote_wakeup;

spin_lock_irqsave(&xhci->lock, flags);

- if (hcd->self.root_hub->do_remote_wakeup) { + if (wake_enabled) { if (bus_state->resuming_ports || /* USB2 */ bus_state->port_remote_wakeup) { /* USB3 */ spin_unlock_irqrestore(&xhci->lock, flags); @@ -1490,26 +1493,36 @@ int xhci_bus_suspend(struct usb_hcd *hcd) return -EBUSY; } } - - port_index = max_ports; + /* + * Prepare ports for suspend, but don't write anything before all ports + * are checked and we know bus suspend can proceed + */ bus_state->bus_suspended = 0; + port_index = max_ports; while (port_index--) { - /* suspend the port if the port is not suspended */ u32 t1, t2; - int slot_id;

t1 = readl(ports[port_index]->addr); t2 = xhci_port_state_to_neutral(t1); + portsc_buf[port_index] = 0;

- if ((t1 & PORT_PE) && !(t1 & PORT_PLS_MASK)) { - xhci_dbg(xhci, "port %d not suspended\n", port_index); - slot_id = xhci_find_slot_id_by_port(hcd, xhci, - port_index + 1); - if (slot_id) { + /* Bail out if a USB3 port has a new device in link training */ + if ((t1 & PORT_PLS_MASK) == XDEV_POLLING) { + bus_state->bus_suspended = 0; + spin_unlock_irqrestore(&xhci->lock, flags); + xhci_dbg(xhci, "Bus suspend bailout, port in polling\n"); + return -EBUSY; + } + + /* suspend ports in U0, or bail out for new connect changes */ + if ((t1 & PORT_PE) && (t1 & PORT_PLS_MASK) == XDEV_U0) { + if ((t1 & PORT_CSC) && wake_enabled) { + bus_state->bus_suspended = 0; spin_unlock_irqrestore(&xhci->lock, flags); - xhci_stop_device(xhci, slot_id, 1); - spin_lock_irqsave(&xhci->lock, flags); + xhci_dbg(xhci, "Bus suspend bailout, port connect change\n"); + return -EBUSY; } + xhci_dbg(xhci, "port %d not suspended\n", port_index); t2 &= ~PORT_PLS_MASK; t2 |= PORT_LINK_STROBE | XDEV_U3; set_bit(port_index, &bus_state->bus_suspended); @@ -1518,7 +1531,7 @@ int xhci_bus_suspend(struct usb_hcd *hcd) * including the USB 3.0 roothub, but only if CONFIG_PM * is enabled, so also enable remote wake here. */ - if (hcd->self.root_hub->do_remote_wakeup) { + if (wake_enabled) { if (t1 & PORT_CONNECT) { t2 |= PORT_WKOC_E | PORT_WKDISC_E; t2 &= ~PORT_WKCONN_E; @@ -1538,7 +1551,26 @@ int xhci_bus_suspend(struct usb_hcd *hcd)

t1 = xhci_port_state_to_neutral(t1); if (t1 != t2) - writel(t2, ports[port_index]->addr); + portsc_buf[port_index] = t2; + } + + /* write port settings, stopping and suspending ports if needed */ + port_index = max_ports; + while (port_index--) { + if (!portsc_buf[port_index]) + continue; + if (test_bit(port_index, &bus_state->bus_suspended)) { + int slot_id; + + slot_id = xhci_find_slot_id_by_port(hcd, xhci, + port_index + 1); + if (slot_id) { + spin_unlock_irqrestore(&xhci->lock, flags); + xhci_stop_device(xhci, slot_id, 1); + spin_lock_irqsave(&xhci->lock, flags); + } + } + writel(portsc_buf[port_index], ports[port_index]->addr); } hcd->state = HC_STATE_SUSPENDED; bus_state->next_statechange = jiffies + msecs_to_jiffies(10);