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@xxxxxxxxxxxxxxxxxxx>
Cc: Kukjin Kim <kgene.kim@xxxxxxxxxxx>
Cc: Vincent Palatin <vpalatin@xxxxxxxxxxxx>
Cc: Lan Tianyu <tianyu.lan@xxxxxxxxx>
Cc: Ksenia Ragiadakou <burzalodowa@xxxxxxxxx>
Cc: Vivek Gautam <gautam.vivek@xxxxxxxxxxx>
Cc: Douglas Anderson <dianders@xxxxxxxxxxxx>
Cc: Felipe Balbi <balbi@xxxxxx>
Cc: Sunil Joshi <joshi@xxxxxxxxxxx>
Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
Acked-by: Julius Werner <jwerner@xxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/usb/core/hub.c | 23 ++++++++++++++++-------
drivers/usb/core/hub.h | 2 ++
drivers/usb/core/port.c | 21 ++++++++++++---------
3 files changed, 30 insertions(+), 16 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index df4a9f587502..573faa097d03 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2570,10 +2570,12 @@ 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) ==
+ (test_bit(port1, hub->warm_reset_bits) ||
+ ((portstatus & USB_PORT_STAT_LINK_STATE) ==
USB_SS_PORT_LS_SS_INACTIVE) ||
((portstatus & USB_PORT_STAT_LINK_STATE) ==
USB_SS_PORT_LS_COMP_MOD)) ;
@@ -2613,7 +2615,7 @@ 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? */
@@ -2713,8 +2715,9 @@ 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 */
@@ -2752,7 +2755,8 @@ 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;
/*
@@ -2839,8 +2843,13 @@ 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 (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)
@@ -4848,7 +4857,7 @@ 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 0a7cdc0ef0a9..e60cf1d242e9 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 62036faf56c0..1c1dd2127816 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -100,16 +100,19 @@ 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)) {
--
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