[PATCH 4.9 213/240] usb: core: hub: fix race condition about TRSMRCY of resume

Greg Kroah-Hartman
2021-05-20T11:24:24Z

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
@@ -3486,9 +3486,6 @@ int usb_port_resume(struct usb_device *u
* sequence.
*/
status = hub_port_status(hub, port1, &portstatus, &portchange);
-
- /* TRSMRCY = 10 msec */
- msleep(10);
}

SuspendCleared:
@@ -3503,6 +3500,9 @@ 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)