Commit f59f93cd authored by Mathias Nyman's avatar Mathias Nyman Committed by Greg Kroah-Hartman
Browse files

usb: hub: avoid warm port reset during USB3 disconnect 



During disconnect USB-3 ports often go via SS.Inactive link error state
before the missing terminations are noticed, and link finally goes to
RxDetect state

Avoid immediately warm-resetting ports in SS.Inactive state.
Let ports settle for a while and re-read the link status a few times 20ms
apart to see if the ports transitions out of SS.Inactive.

According to USB 3.x spec 7.5.2, a port in SS.Inactive should
automatically check for missing far-end receiver termination every
12 ms (SSInactiveQuietTimeout)

The futile multiple warm reset retries of a disconnected device takes
a lot of time, also the resetting of a removed devices has caused cases
where the reset bit got stuck for a long time on xHCI roothub.
This lead to issues in detecting new devices connected to the same port
shortly after.

Tested-by: default avatarMark Pearson <markpearson@lenovo.com>
Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20211210111653.1378381-1-mathias.nyman@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a1f79504

drivers/usb/core/hub.c

+19 −5
Original line number Diff line number Diff line
@@ -2777,6 +2777,8 @@ static unsigned hub_is_wusb(struct usb_hub *hub) 
#define PORT_INIT_TRIES		4

#endif	/* CONFIG_USB_FEW_INIT_RETRIES */



#define DETECT_DISCONNECT_TRIES 5



#define HUB_ROOT_RESET_TIME	60	/* times are in msec */

#define HUB_SHORT_RESET_TIME	10

#define HUB_BH_RESET_TIME	50
@@ -5543,6 +5545,7 @@ static void port_event(struct usb_hub *hub, int port1) 
	struct usb_device *udev = port_dev->child;

	struct usb_device *hdev = hub->hdev;

	u16 portstatus, portchange;

	int i = 0;



	connect_change = test_bit(port1, hub->change_bits);

	clear_bit(port1, hub->event_bits);
@@ -5619,17 +5622,27 @@ static void port_event(struct usb_hub *hub, int port1) 
		connect_change = 1;



	/*

	 * Warm reset a USB3 protocol port if it's in

	 * SS.Inactive state.

	 * Avoid trying to recover a USB3 SS.Inactive port with a warm reset if

	 * the device was disconnected. A 12ms disconnect detect timer in

	 * SS.Inactive state transitions the port to RxDetect automatically.

	 * SS.Inactive link error state is common during device disconnect.

	 */

	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)

	while (hub_port_warm_reset_required(hub, port1, portstatus)) {

		if ((i++ < DETECT_DISCONNECT_TRIES) && udev) {

			u16 unused;



			msleep(20);

			hub_port_status(hub, port1, &portstatus, &unused);

			dev_dbg(&port_dev->dev, "Wait for inactive link disconnect detect\n");

			continue;

		} else if (!udev || !(portstatus & USB_PORT_STAT_CONNECTION)

				|| udev->state == USB_STATE_NOTATTACHED) {

			dev_dbg(&port_dev->dev, "do warm reset, port only\n");

			if (hub_port_reset(hub, port1, NULL,

					HUB_BH_RESET_TIME, true) < 0)

				hub_port_disable(hub, port1, 1);

		} else {

			dev_dbg(&port_dev->dev, "do warm reset, full device\n");

			usb_unlock_port(port_dev);

			usb_lock_device(udev);

			usb_reset_device(udev);
@@ -5637,6 +5650,7 @@ static void port_event(struct usb_hub *hub, int port1) 
			usb_lock_port(port_dev);

			connect_change = 0;

		}

		break;

	}



	if (connect_change)