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authorDan Williams <dan.j.williams@intel.com>2014-05-29 12:58:46 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-07-09 15:43:12 -0700
commit3cd12f91514da6893954de479dc60b16d3b381f4 (patch)
tree3209b05551050ac2e1da7f79ca96bc49298f9ac9 /drivers/usb/core
parent51df62ff74b371866c1006dee887a8e42838c1f2 (diff)
downloadlinux-stericsson-3cd12f91514da6893954de479dc60b16d3b381f4.tar.gz
usb: force warm reset to break link re-connect livelock
Resuming a powered down port sometimes results in the port state being stuck in the training sequence. hub 3-0:1.0: debounce: port 1: total 2000ms stable 0ms status 0x2e0 port1: can't get reconnection after setting port power on, status -110 hub 3-0:1.0: port 1 status 0000.02e0 after resume, -19 usb 3-1: can't resume, status -19 hub 3-0:1.0: logical disconnect on port 1 In the case above we wait for the port re-connect timeout of 2 seconds and observe that the port status is USB_SS_PORT_LS_POLLING (although it is likely toggling between this state and USB_SS_PORT_LS_RX_DETECT). This is indicative of a case where the device is failing to progress the link training state machine. It is resolved by issuing a warm reset to get the hub and device link state machines back in sync. hub 3-0:1.0: debounce: port 1: total 2000ms stable 0ms status 0x2e0 usb usb3: port1 usb_port_runtime_resume requires warm reset hub 3-0:1.0: port 1 not warm reset yet, waiting 50ms usb 3-1: reset SuperSpeed USB device number 2 using xhci_hcd After a reconnect timeout when we expect the device to be present, force a warm reset of the device. Note that we can not simply look at the link status to determine if a warm reset is required as any of the training states USB_SS_PORT_LS_POLLING, USB_SS_PORT_LS_RX_DETECT, or USB_SS_PORT_LS_COMP_MOD are valid states that do not indicate the need for warm reset by themselves. Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Kukjin Kim <kgene.kim@samsung.com> Cc: Vincent Palatin <vpalatin@chromium.org> Cc: Lan Tianyu <tianyu.lan@intel.com> Cc: Ksenia Ragiadakou <burzalodowa@gmail.com> Cc: Vivek Gautam <gautam.vivek@samsung.com> Cc: Douglas Anderson <dianders@chromium.org> Cc: Felipe Balbi <balbi@ti.com> Cc: Sunil Joshi <joshi@samsung.com> Cc: Hans de Goede <hdegoede@redhat.com> Acked-by: Julius Werner <jwerner@chromium.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/core')
-rw-r--r--drivers/usb/core/hub.c36
-rw-r--r--drivers/usb/core/hub.h2
-rw-r--r--drivers/usb/core/port.c21
3 files changed, 39 insertions, 20 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index b90c6287bf47..88f1db27e0af 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2587,13 +2587,20 @@ static int hub_port_reset(struct usb_hub *hub, int port1,
/* Is a USB 3.0 port in the Inactive or Compliance Mode state?
* Port worm reset is required to recover
*/
-static bool hub_port_warm_reset_required(struct usb_hub *hub, u16 portstatus)
+static bool hub_port_warm_reset_required(struct usb_hub *hub, int port1,
+ u16 portstatus)
{
- return hub_is_superspeed(hub->hdev) &&
- (((portstatus & USB_PORT_STAT_LINK_STATE) ==
- USB_SS_PORT_LS_SS_INACTIVE) ||
- ((portstatus & USB_PORT_STAT_LINK_STATE) ==
- USB_SS_PORT_LS_COMP_MOD)) ;
+ u16 link_state;
+
+ if (!hub_is_superspeed(hub->hdev))
+ return false;
+
+ if (test_bit(port1, hub->warm_reset_bits))
+ return true;
+
+ link_state = portstatus & USB_PORT_STAT_LINK_STATE;
+ return link_state == USB_SS_PORT_LS_SS_INACTIVE
+ || link_state == USB_SS_PORT_LS_COMP_MOD;
}
static int hub_port_wait_reset(struct usb_hub *hub, int port1,
@@ -2630,7 +2637,7 @@ static int hub_port_wait_reset(struct usb_hub *hub, int port1,
if ((portstatus & USB_PORT_STAT_RESET))
return -EBUSY;
- if (hub_port_warm_reset_required(hub, portstatus))
+ if (hub_port_warm_reset_required(hub, port1, portstatus))
return -ENOTCONN;
/* Device went away? */
@@ -2730,9 +2737,10 @@ static int hub_port_reset(struct usb_hub *hub, int port1,
if (status < 0)
goto done;
- if (hub_port_warm_reset_required(hub, portstatus))
+ if (hub_port_warm_reset_required(hub, port1, portstatus))
warm = true;
}
+ clear_bit(port1, hub->warm_reset_bits);
/* Reset the port */
for (i = 0; i < PORT_RESET_TRIES; i++) {
@@ -2769,7 +2777,8 @@ static int hub_port_reset(struct usb_hub *hub, int port1,
&portstatus, &portchange) < 0)
goto done;
- if (!hub_port_warm_reset_required(hub, portstatus))
+ if (!hub_port_warm_reset_required(hub, port1,
+ portstatus))
goto done;
/*
@@ -2856,8 +2865,13 @@ static int check_port_resume_type(struct usb_device *udev,
{
struct usb_port *port_dev = hub->ports[port1 - 1];
+ /* Is a warm reset needed to recover the connection? */
+ if (status == 0 && udev->reset_resume
+ && hub_port_warm_reset_required(hub, port1, portstatus)) {
+ /* pass */;
+ }
/* Is the device still present? */
- if (status || port_is_suspended(hub, portstatus) ||
+ else if (status || port_is_suspended(hub, portstatus) ||
!port_is_power_on(hub, portstatus) ||
!(portstatus & USB_PORT_STAT_CONNECTION)) {
if (status >= 0)
@@ -4872,7 +4886,7 @@ static void port_event(struct usb_hub *hub, int port1)
* Warm reset a USB3 protocol port if it's in
* SS.Inactive state.
*/
- if (hub_port_warm_reset_required(hub, portstatus)) {
+ if (hub_port_warm_reset_required(hub, port1, portstatus)) {
dev_dbg(&port_dev->dev, "do warm reset\n");
if (!udev || !(portstatus & USB_PORT_STAT_CONNECTION)
|| udev->state == USB_STATE_NOTATTACHED) {
diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
index 326308e53961..c77d8778af4b 100644
--- a/drivers/usb/core/hub.h
+++ b/drivers/usb/core/hub.h
@@ -52,6 +52,8 @@ struct usb_hub {
unsigned long power_bits[1]; /* ports that are powered */
unsigned long child_usage_bits[1]; /* ports powered on for
children */
+ unsigned long warm_reset_bits[1]; /* ports requesting warm
+ reset recovery */
#if USB_MAXCHILDREN > 31 /* 8*sizeof(unsigned long) - 1 */
#error event_bits[] is too short!
#endif
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index fe1b6d0967e3..cd3f9dc24a06 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -103,16 +103,19 @@ static int usb_port_runtime_resume(struct device *dev)
msleep(hub_power_on_good_delay(hub));
if (udev && !retval) {
/*
- * Attempt to wait for usb hub port to be reconnected in order
- * to make the resume procedure successful. The device may have
- * disconnected while the port was powered off, so ignore the
- * return status.
+ * Our preference is to simply wait for the port to reconnect,
+ * as that is the lowest latency method to restart the port.
+ * However, there are cases where toggling port power results in
+ * the host port and the device port getting out of sync causing
+ * a link training live lock. Upon timeout, flag the port as
+ * needing warm reset recovery (to be performed later by
+ * usb_port_resume() as requested via usb_wakeup_notification())
*/
- retval = hub_port_debounce_be_connected(hub, port1);
- if (retval < 0)
- dev_dbg(&port_dev->dev, "can't get reconnection after setting port power on, status %d\n",
- retval);
- retval = 0;
+ if (hub_port_debounce_be_connected(hub, port1) < 0) {
+ dev_dbg(&port_dev->dev, "reconnect timeout\n");
+ if (hub_is_superspeed(hdev))
+ set_bit(port1, hub->warm_reset_bits);
+ }
/* Force the child awake to revalidate after the power loss. */
if (!test_and_set_bit(port1, hub->child_usage_bits)) {