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From cb82a54904a99df9e8f9e9d282046055dae5a730 Mon Sep 17 00:00:00 2001
From: Leon Schuermann <leon@is.currently.online>
Date: Mon, 11 Jan 2021 20:03:13 +0100
Subject: [PATCH] r8152: Add Lenovo Powered USB-C Travel Hub
Git-commit: cb82a54904a99df9e8f9e9d282046055dae5a730
Patch-mainline: v5.11-rc4
References: git-fixes

This USB-C Hub (17ef:721e) based on the Realtek RTL8153B chip used to
use the cdc_ether driver. However, using this driver, with the system
suspended the device constantly sends pause-frames as soon as the
receive buffer fills up. This causes issues with other devices, where
some Ethernet switches stop forwarding packets altogether.

Using the Realtek driver (r8152) fixes this issue. Pause frames are no
longer sent while the host system is suspended.

Signed-off-by: Leon Schuermann <leon@is.currently.online>
Tested-by: Leon Schuermann <leon@is.currently.online>
Link: https://lore.kernel.org/r/20210111190312.12589-2-leon@is.currently.online
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/net/usb/cdc_ether.c | 7 +++++++
 drivers/net/usb/r8152.c     | 1 +
 2 files changed, 8 insertions(+)

diff --git a/drivers/net/usb/cdc_ether.c b/drivers/net/usb/cdc_ether.c
index 8c1d61c2cbac..6aaa0675c28a 100644
--- a/drivers/net/usb/cdc_ether.c
+++ b/drivers/net/usb/cdc_ether.c
@@ -793,6 +793,13 @@ static const struct usb_device_id	products[] = {
 	.driver_info = 0,
 },
 
+/* Lenovo Powered USB-C Travel Hub (4X90S92381, based on Realtek RTL8153) */
+{
+	USB_DEVICE_AND_INTERFACE_INFO(LENOVO_VENDOR_ID, 0x721e, USB_CLASS_COMM,
+			USB_CDC_SUBCLASS_ETHERNET, USB_CDC_PROTO_NONE),
+	.driver_info = 0,
+},
+
 /* ThinkPad USB-C Dock Gen 2 (based on Realtek RTL8153) */
 {
 	USB_DEVICE_AND_INTERFACE_INFO(LENOVO_VENDOR_ID, 0xa387, USB_CLASS_COMM,
diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index c448d6089821..67cd6986634f 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -6877,6 +6877,7 @@ static const struct usb_device_id rtl8152_table[] = {
 	{REALTEK_USB_DEVICE(VENDOR_ID_LENOVO,  0x7205)},
 	{REALTEK_USB_DEVICE(VENDOR_ID_LENOVO,  0x720c)},
 	{REALTEK_USB_DEVICE(VENDOR_ID_LENOVO,  0x7214)},
+	{REALTEK_USB_DEVICE(VENDOR_ID_LENOVO,  0x721e)},
 	{REALTEK_USB_DEVICE(VENDOR_ID_LENOVO,  0xa387)},
 	{REALTEK_USB_DEVICE(VENDOR_ID_LINKSYS, 0x0041)},
 	{REALTEK_USB_DEVICE(VENDOR_ID_NVIDIA,  0x09ff)},
-- 
2.26.2