blob: 87afd28c4cd9f6a4c8ca6ee7a9a4cf3cd4b44694 [file] [log] [blame]
From 751f65aeec205eb72c33c07e8b7e50449d811ba9 Mon Sep 17 00:00:00 2001
From: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Date: Tue, 20 Aug 2013 08:12:12 -0700
Subject: usb: Fix xHCI host issues on remote wakeup.
When a device signals remote wakeup on a roothub, and the suspend change
bit is set, the host controller driver must not give control back to the
USB core until the port goes back into the active state.
EHCI accomplishes this by waiting in the get port status function until
the PORT_RESUME bit is cleared:
/* stop resume signaling */
temp &= ~(PORT_RWC_BITS | PORT_SUSPEND | PORT_RESUME);
ehci_writel(ehci, temp, status_reg);
clear_bit(wIndex, &ehci->resuming_ports);
retval = ehci_handshake(ehci, status_reg,
PORT_RESUME, 0, 2000 /* 2msec */);
Similarly, the xHCI host should wait until the port goes into U0, before
passing control up to the USB core. When the port transitions from the
RExit state to U0, the xHCI driver will get a port status change event.
We need to wait for that event before passing control up to the USB
core.
After the port transitions to the active state, the USB core should time
a recovery interval before it talks to the device. The length of that
recovery interval is TRSMRCY, 10 ms, mentioned in the USB 2.0 spec,
section 7.1.7.7. The previous xHCI code (which did not wait for the
port to go into U0) would cause the USB core to violate that recovery
interval.
This bug caused numerous USB device disconnects on remote wakeup under
ChromeOS and a Lynx Point LP xHCI host that takes up to 20 ms to move
from RExit to U0. ChromeOS is very aggressive about power savings, and
sets the autosuspend_delay to 100 ms, and disables USB persist.
I attempted to replicate this bug with Ubuntu 12.04, but could not. I
used Ubuntu 12.04 on the same platform, with the same BIOS that the bug
was triggered on ChromeOS with. I also changed the USB sysfs settings
as described above, but still could not reproduce the bug under Ubuntu.
It may be that ChromeOS userspace triggers this bug through additional
settings.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
(cherry picked from commit 8b3d45705e54075cfb9d4212dbca9ea82c85c4b8)
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
---
drivers/usb/host/xhci-hub.c | 45 +++++++++++++++++++++++++++++++++----------
drivers/usb/host/xhci-mem.c | 2 +
drivers/usb/host/xhci-ring.c | 13 ++++++++++++
drivers/usb/host/xhci.h | 10 +++++++++
4 files changed, 60 insertions(+), 10 deletions(-)
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -550,11 +550,15 @@ void xhci_del_comp_mod_timer(struct xhci
* - Mark a port as being done with device resume,
* and ring the endpoint doorbells.
* - Stop the Synopsys redriver Compliance Mode polling.
+ * - Drop and reacquire the xHCI lock, in order to wait for port resume.
*/
static u32 xhci_get_port_status(struct usb_hcd *hcd,
struct xhci_bus_state *bus_state,
__le32 __iomem **port_array,
- u16 wIndex, u32 raw_port_status)
+ u16 wIndex, u32 raw_port_status,
+ unsigned long flags)
+ __releases(&xhci->lock)
+ __acquires(&xhci->lock)
{
struct xhci_hcd *xhci = hcd_to_xhci(hcd);
u32 status = 0;
@@ -589,21 +593,42 @@ static u32 xhci_get_port_status(struct u
return 0xffffffff;
if (time_after_eq(jiffies,
bus_state->resume_done[wIndex])) {
+ int time_left;
+
xhci_dbg(xhci, "Resume USB2 port %d\n",
wIndex + 1);
bus_state->resume_done[wIndex] = 0;
clear_bit(wIndex, &bus_state->resuming_ports);
+
+ set_bit(wIndex, &bus_state->rexit_ports);
xhci_set_link_state(xhci, port_array, wIndex,
XDEV_U0);
- xhci_dbg(xhci, "set port %d resume\n",
- wIndex + 1);
- slot_id = xhci_find_slot_id_by_port(hcd, xhci,
- wIndex + 1);
- if (!slot_id) {
- xhci_dbg(xhci, "slot_id is zero\n");
- return 0xffffffff;
+
+ spin_unlock_irqrestore(&xhci->lock, flags);
+ time_left = wait_for_completion_timeout(
+ &bus_state->rexit_done[wIndex],
+ msecs_to_jiffies(
+ XHCI_MAX_REXIT_TIMEOUT));
+ spin_lock_irqsave(&xhci->lock, flags);
+
+ if (time_left) {
+ slot_id = xhci_find_slot_id_by_port(hcd,
+ xhci, wIndex + 1);
+ if (!slot_id) {
+ xhci_dbg(xhci, "slot_id is zero\n");
+ return 0xffffffff;
+ }
+ xhci_ring_device(xhci, slot_id);
+ } else {
+ int port_status = xhci_readl(xhci,
+ port_array[wIndex]);
+ xhci_warn(xhci, "Port resume took longer than %i msec, port status = 0x%x\n",
+ XHCI_MAX_REXIT_TIMEOUT,
+ port_status);
+ status |= USB_PORT_STAT_SUSPEND;
+ clear_bit(wIndex, &bus_state->rexit_ports);
}
- xhci_ring_device(xhci, slot_id);
+
bus_state->port_c_suspend |= 1 << wIndex;
bus_state->suspended_ports &= ~(1 << wIndex);
} else {
@@ -724,7 +749,7 @@ int xhci_hub_control(struct usb_hcd *hcd
break;
}
status = xhci_get_port_status(hcd, bus_state, port_array,
- wIndex, temp);
+ wIndex, temp, flags);
if (status == 0xffffffff)
goto error;
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -2487,6 +2487,8 @@ int xhci_mem_init(struct xhci_hcd *xhci,
for (i = 0; i < USB_MAXCHILDREN; ++i) {
xhci->bus_state[0].resume_done[i] = 0;
xhci->bus_state[1].resume_done[i] = 0;
+ /* Only the USB 2.0 completions will ever be used. */
+ init_completion(&xhci->bus_state[1].rexit_done[i]);
}
if (scratchpad_alloc(xhci, flags))
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1734,6 +1734,19 @@ static void handle_port_status(struct xh
}
}
+ /*
+ * Check to see if xhci-hub.c is waiting on RExit to U0 transition (or
+ * RExit to a disconnect state). If so, let the the driver know it's
+ * out of the RExit state.
+ */
+ if (!DEV_SUPERSPEED(temp) &&
+ test_and_clear_bit(faked_port_index,
+ &bus_state->rexit_ports)) {
+ complete(&bus_state->rexit_done[faked_port_index]);
+ bogus_port_status = true;
+ goto cleanup;
+ }
+
if (hcd->speed != HCD_USB3)
xhci_test_and_clear_bit(xhci, port_array, faked_port_index,
PORT_PLC);
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1391,8 +1391,18 @@ struct xhci_bus_state {
unsigned long resume_done[USB_MAXCHILDREN];
/* which ports have started to resume */
unsigned long resuming_ports;
+ /* Which ports are waiting on RExit to U0 transition. */
+ unsigned long rexit_ports;
+ struct completion rexit_done[USB_MAXCHILDREN];
};
+
+/*
+ * It can take up to 20 ms to transition from RExit to U0 on the
+ * Intel Lynx Point LP xHCI host.
+ */
+#define XHCI_MAX_REXIT_TIMEOUT (20 * 1000)
+
static inline unsigned int hcd_index(struct usb_hcd *hcd)
{
if (hcd->speed == HCD_USB3)