patch "usb: Handle USB3 remote wakeup for LPM enabled devices correctly" added to usb-testing

patch "usb: Handle USB3 remote wakeup for LPM enabled devices correctly" added to usb-testing

[gregkh]

This is a note to let you know that I've just added the patch titled

    usb: Handle USB3 remote wakeup for LPM enabled devices correctly

to my usb git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-testing branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will be merged to the usb-next branch sometime soon,
after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.


From e244c4699f859cf7149b0781b1894c7996a8a1df Mon Sep 17 00:00:00 2001
From: "Lee, Chiasheng" <chiasheng.lee@intel.com>
Date: Thu, 20 Jun 2019 10:56:04 +0300
Subject: usb: Handle USB3 remote wakeup for LPM enabled devices correctly

With Link Power Management (LPM) enabled USB3 links transition to low
power U1/U2 link states from U0 state automatically.

Current hub code detects USB3 remote wakeups by checking if the software
state still shows suspended, but the link has transitioned from suspended
U3 to enabled U0 state.

As it takes some time before the hub thread reads the port link state
after a USB3 wake notification, the link may have transitioned from U0
to U1/U2, and wake is not detected by hub code.

Fix this by handling U1/U2 states in the same way as U0 in USB3 wakeup
handling

This patch should be added to stable kernels since 4.13 where LPM was
kept enabled during suspend/resume

Cc: <stable@vger.kernel.org> # v4.13+
Signed-off-by: Lee, Chiasheng <chiasheng.lee@intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/core/hub.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index a59e1573b43b..236313f41f4a 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3619,6 +3619,7 @@ static int hub_handle_remote_wakeup(struct usb_hub *hub, unsigned int port,
 	struct usb_device *hdev;
 	struct usb_device *udev;
 	int connect_change = 0;
+	u16 link_state;
 	int ret;
 
 	hdev = hub->hdev;
@@ -3628,9 +3629,11 @@ static int hub_handle_remote_wakeup(struct usb_hub *hub, unsigned int port,
 			return 0;
 		usb_clear_port_feature(hdev, port, USB_PORT_FEAT_C_SUSPEND);
 	} else {
+		link_state = portstatus & USB_PORT_STAT_LINK_STATE;
 		if (!udev || udev->state != USB_STATE_SUSPENDED ||
-				 (portstatus & USB_PORT_STAT_LINK_STATE) !=
-				 USB_SS_PORT_LS_U0)
+				(link_state != USB_SS_PORT_LS_U0 &&
+				 link_state != USB_SS_PORT_LS_U1 &&
+				 link_state != USB_SS_PORT_LS_U2))
 			return 0;
 	}
 
-- 
2.22.0