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From:   Kai-Heng Feng <kai.heng.feng@canonical.com>
To:     gregkh@linuxfoundation.org
Cc:     stern@rowland.harvard.edu, mathias.nyman@intel.com,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Kai-Heng Feng <kai.heng.feng@canonical.com>
Subject: [PATCH v2] usb: Add a new quirk to let buggy hub enable and disable LPM during suspend and resume
Date:   Thu,  3 Oct 2019 23:56:40 +0800
Message-Id: <20191003155640.12632-1-kai.heng.feng@canonical.com>
In-Reply-To: <20191002151512.28517-1-kai.heng.feng@canonical.com>
References: <20191002151512.28517-1-kai.heng.feng@canonical.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Dell WD15 dock has a topology like this:
/:  Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 10000M
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/7p, 5000M
            |__ Port 2: Dev 3, If 0, Class=Vendor Specific Class, Driver=r8152, 5000M

Their IDs:
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 004 Device 002: ID 0424:5537 Standard Microsystems Corp.
Bus 004 Device 004: ID 0bda:8153 Realtek Semiconductor Corp.

Ethernet cannot be detected after plugging ethernet cable to the dock,
the hub and roothub get runtime resumed and runtime suspended
immediately:
...
[  433.315169] xhci_hcd 0000:3a:00.0: hcd_pci_runtime_resume: 0
[  433.315204] usb usb4: usb auto-resume
[  433.315226] hub 4-0:1.0: hub_resume
[  433.315239] xhci_hcd 0000:3a:00.0: Get port status 4-1 read: 0x10202e2, return 0x10343
[  433.315264] usb usb4-port1: status 0343 change 0001
[  433.315279] xhci_hcd 0000:3a:00.0: clear port1 connect change, portsc: 0x10002e2
[  433.315293] xhci_hcd 0000:3a:00.0: Get port status 4-2 read: 0x2a0, return 0x2a0
[  433.317012] xhci_hcd 0000:3a:00.0: xhci_hub_status_data: stopping port polling.
[  433.422282] xhci_hcd 0000:3a:00.0: Get port status 4-1 read: 0x10002e2, return 0x343

At this point the SMSC hub (usb 4-1) enters into compliance mode
(USB_SS_PORT_LS_COMP_MOD), and USB core tries to warm-reset it,

[  433.422307] usb usb4-port1: do warm reset
[  433.422311] usb 4-1: device reset not allowed in state 8
[  433.422339] hub 4-0:1.0: state 7 ports 2 chg 0002 evt 0000
[  433.422346] xhci_hcd 0000:3a:00.0: Get port status 4-1 read: 0x10002e2, return 0x343
[  433.422356] usb usb4-port1: do warm reset
[  433.422358] usb 4-1: device reset not allowed in state 8
[  433.422428] xhci_hcd 0000:3a:00.0: set port remote wake mask, actual port 0 status  = 0xf0002e2
[  433.422455] xhci_hcd 0000:3a:00.0: set port remote wake mask, actual port 1 status  = 0xe0002a0
[  433.422465] hub 4-0:1.0: hub_suspend
[  433.422475] usb usb4: bus auto-suspend, wakeup 1
[  433.426161] xhci_hcd 0000:3a:00.0: xhci_hub_status_data: stopping port polling.
[  433.466209] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[  433.510204] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[  433.554051] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[  433.598235] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[  433.642154] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[  433.686204] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[  433.730205] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[  433.774203] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[  433.818207] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[  433.862040] xhci_hcd 0000:3a:00.0: port 0 polling in bus suspend, waiting
[  433.862053] xhci_hcd 0000:3a:00.0: xhci_hub_status_data: stopping port polling.
[  433.862077] xhci_hcd 0000:3a:00.0: xhci_suspend: stopping port polling.
[  433.862096] xhci_hcd 0000:3a:00.0: // Setting command ring address to 0x8578fc001
[  433.862312] xhci_hcd 0000:3a:00.0: hcd_pci_runtime_suspend: 0
[  433.862445] xhci_hcd 0000:3a:00.0: PME# enabled
[  433.902376] xhci_hcd 0000:3a:00.0: restoring config space at offset 0xc (was 0x0, writing 0x20)
[  433.902395] xhci_hcd 0000:3a:00.0: restoring config space at offset 0x4 (was 0x100000, writing 0x100403)
[  433.902490] xhci_hcd 0000:3a:00.0: PME# disabled
[  433.902504] xhci_hcd 0000:3a:00.0: enabling bus mastering
[  433.902547] xhci_hcd 0000:3a:00.0: // Setting command ring address to 0x8578fc001
[  433.902649] pcieport 0000:00:1b.0: PME: Spurious native interrupt!
[  433.902839] xhci_hcd 0000:3a:00.0: Port change event, 4-1, id 3, portsc: 0xb0202e2
[  433.902842] xhci_hcd 0000:3a:00.0: resume root hub
[  433.902845] xhci_hcd 0000:3a:00.0: handle_port_status: starting port polling.
[  433.902877] xhci_hcd 0000:3a:00.0: xhci_resume: starting port polling.
[  433.902889] xhci_hcd 0000:3a:00.0: xhci_hub_status_data: stopping port polling.
[  433.902891] xhci_hcd 0000:3a:00.0: hcd_pci_runtime_resume: 0
[  433.902919] usb usb4: usb wakeup-resume
[  433.902942] usb usb4: usb auto-resume
[  433.902966] hub 4-0:1.0: hub_resume
...

However the warm-reset never success, the asserted PCI PME keeps the
runtime-resume, warm-reset and runtime-suspend loop which never bring it back
and causing spurious interrupts floods.

After some trial and errors, the issue goes away if LPM on the SMSC hub
is disabled. Digging further, enabling and disabling LPM during runtime
resume and runtime suspend respectively can solve the issue.

So bring back the old LPM behavior as a quirk and use it for the SMSC
hub to solve the issue.

Fixes: d590c2311150 ("usb: Avoid unnecessary LPM enabling and disabling during suspend and resume")
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 Documentation/admin-guide/kernel-parameters.txt |  3 +++
 drivers/usb/core/hub.c                          | 15 +++++++++++++++
 drivers/usb/core/quirks.c                       |  6 ++++++
 include/linux/usb/quirks.h                      |  3 +++
 4 files changed, 27 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index c7ac2f3ac99f..0b5ba2545373 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4974,6 +4974,9 @@
 					pause after every control message);
 				o = USB_QUIRK_HUB_SLOW_RESET (Hub needs extra
 					delay after resetting its port);
+				p = USB_QUIRK_PM_SET_LPM (Device needs to
+					disable LPM on suspend and enable LPM
+					on resume);
 			Example: quirks=0781:5580:bk,0a5c:5834:gij
 
 	usbhid.mousepoll=
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 236313f41f4a..5e07407c8204 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3269,6 +3269,13 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
 		if (PMSG_IS_AUTO(msg))
 			goto err_ltm;
 	}
+	if (udev->quirks & USB_QUIRK_PM_SET_LPM &&
+	    usb_unlocked_disable_lpm(udev)) {
+		dev_err(&udev->dev, "Failed to disable LPM before suspend\n.");
+		status = -ENOMEM;
+		if (PMSG_IS_AUTO(msg))
+			goto err_lpm3;
+	}
 
 	/* see 7.1.7.6 */
 	if (hub_is_superspeed(hub->hdev))
@@ -3295,6 +3302,10 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
 	if (status) {
 		dev_dbg(&port_dev->dev, "can't suspend, status %d\n", status);
 
+		/* Try to enable USB3 LPM again */
+		if (udev->quirks & USB_QUIRK_PM_SET_LPM)
+			usb_unlocked_enable_lpm(udev);
+ err_lpm3:
 		/* Try to enable USB3 LTM again */
 		usb_enable_ltm(udev);
  err_ltm:
@@ -3586,6 +3597,10 @@ int usb_port_resume(struct usb_device *udev, pm_message_t msg)
 
 		/* Try to enable USB3 LTM */
 		usb_enable_ltm(udev);
+
+		/* Try to enable USB3 LPM */
+		if (udev->quirks & USB_QUIRK_PM_SET_LPM)
+			usb_unlocked_enable_lpm(udev);
 	}
 
 	usb_unlock_port(port_dev);
diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c
index 6b6413073584..75bbc9faddb4 100644
--- a/drivers/usb/core/quirks.c
+++ b/drivers/usb/core/quirks.c
@@ -131,6 +131,9 @@ static int quirks_param_set(const char *val, const struct kernel_param *kp)
 			case 'o':
 				flags |= USB_QUIRK_HUB_SLOW_RESET;
 				break;
+			case 'p':
+				flags |= USB_QUIRK_PM_SET_LPM;
+				break;
 			/* Ignore unrecognized flag characters */
 			}
 		}
@@ -203,6 +206,9 @@ static const struct usb_device_id usb_quirk_list[] = {
 	/* USB3503 */
 	{ USB_DEVICE(0x0424, 0x3503), .driver_info = USB_QUIRK_RESET_RESUME },
 
+	/* SMSC USB5537B USB 3.0 Hub (Dell WD15) */
+	{ USB_DEVICE(0x0424, 0x5537), .driver_info = USB_QUIRK_PM_SET_LPM },
+
 	/* Microsoft Wireless Laser Mouse 6000 Receiver */
 	{ USB_DEVICE(0x045e, 0x00e1), .driver_info = USB_QUIRK_RESET_RESUME },
 
diff --git a/include/linux/usb/quirks.h b/include/linux/usb/quirks.h
index a1be64c9940f..3f2d97eff369 100644
--- a/include/linux/usb/quirks.h
+++ b/include/linux/usb/quirks.h
@@ -69,4 +69,7 @@
 /* Hub needs extra delay after resetting its port. */
 #define USB_QUIRK_HUB_SLOW_RESET		BIT(14)
 
+/* Device needs to disable LPM on suspend and enable LPM on resume */
+#define USB_QUIRK_PM_SET_LPM			BIT(15)
+
 #endif /* __LINUX_USB_QUIRKS_H */
-- 
2.17.1