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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Tianping Fang <tianping.fang@mediatek.com>,
        Alan Stern <stern@rowland.harvard.edu>,
        Chunfeng Yun <chunfeng.yun@mediatek.com>
Subject: [PATCH 4.4 168/190] usb: core: hub: fix race condition about TRSMRCY of resume
Date:   Thu, 20 May 2021 11:23:52 +0200
Message-Id: <20210520092107.730868243@linuxfoundation.org>
In-Reply-To: <20210520092102.149300807@linuxfoundation.org>
References: <20210520092102.149300807@linuxfoundation.org>
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From: Chunfeng Yun <chunfeng.yun@mediatek.com>

commit 975f94c7d6c306b833628baa9aec3f79db1eb3a1 upstream.

This may happen if the port becomes resume status exactly
when usb_port_resume() gets port status, it still need provide
a TRSMCRY time before access the device.

CC: <stable@vger.kernel.org>
Reported-by: Tianping Fang <tianping.fang@mediatek.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20210512020738.52961-1-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/core/hub.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3430,9 +3430,6 @@ int usb_port_resume(struct usb_device *u
 		 * sequence.
 		 */
 		status = hub_port_status(hub, port1, &portstatus, &portchange);
-
-		/* TRSMRCY = 10 msec */
-		msleep(10);
 	}
 
  SuspendCleared:
@@ -3447,6 +3444,9 @@ int usb_port_resume(struct usb_device *u
 				usb_clear_port_feature(hub->hdev, port1,
 						USB_PORT_FEAT_C_SUSPEND);
 		}
+
+		/* TRSMRCY = 10 msec */
+		msleep(10);
 	}
 
 	if (udev->persist_enabled && hub_is_superspeed(hub->hdev))