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From: "Stephen J. Fuhry" <fuhrysteve@gmail.com>
To: gregkh@linuxfoundation.org
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Stephen J. Fuhry" <fuhrysteve@gmail.com>
Subject: [PATCH] USB: quirks: add NO_LPM for Lenovo ThinkPad USB-C Dock Gen2 hub controllers
Date: Wed, 13 May 2026 13:14:19 -0400	[thread overview]
Message-ID: <20260513171419.44849-1-fuhrysteve@gmail.com> (raw)

The Lenovo ThinkPad USB-C Dock Gen2 (17ef:a391, 17ef:a392) hub
controllers exhibit link instability when USB Link Power Management
is enabled, similar to the dock's Ethernet adapter (17ef:a387) which
already carries USB_QUIRK_NO_LPM.

When the dock reconnects after a transient disconnect, the hub
controllers enter LPM states between re-enumeration retries, causing
repeated disconnect/reconnect cycles lasting up to two minutes.
Disabling LPM for these devices restores stable enumeration.

Signed-off-by: Stephen J. Fuhry <fuhrysteve@gmail.com>
---
 drivers/usb/core/quirks.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c
index 0ffdaefba..87810eff9 100644
--- a/drivers/usb/core/quirks.c
+++ b/drivers/usb/core/quirks.c
@@ -513,6 +513,10 @@ static const struct usb_device_id usb_quirk_list[] = {
 	/* Lenovo ThinkPad USB-C Dock Gen2 Ethernet (RTL8153 GigE) */
 	{ USB_DEVICE(0x17ef, 0xa387), .driver_info = USB_QUIRK_NO_LPM },
 
+	/* Lenovo ThinkPad USB-C Dock Gen2 USB 3.1 and USB 2.0 hub controllers */
+	{ USB_DEVICE(0x17ef, 0xa391), .driver_info = USB_QUIRK_NO_LPM },
+	{ USB_DEVICE(0x17ef, 0xa392), .driver_info = USB_QUIRK_NO_LPM },
+
 	/* BUILDWIN Photo Frame */
 	{ USB_DEVICE(0x1908, 0x1315), .driver_info =
 			USB_QUIRK_HONOR_BNUMINTERFACES },
-- 
2.47.3


                 reply	other threads:[~2026-05-13 17:14 UTC|newest]

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