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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
        "Alan Stern" <stern@rowland.harvard.edu>, "Bin Liu" <b-liu@ti.com>,
        "Alessandro Antenucci" <antenucci@korg.it>
Date:   Sun, 11 Nov 2018 19:49:05 +0000
Message-ID: <lsq.1541965745.996640375@decadent.org.uk>
Subject: [PATCH 3.16 273/366] usb: core: handle hub C_PORT_OVER_CURRENT
 condition
In-Reply-To: <lsq.1541965744.387173642@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Bin Liu <b-liu@ti.com>

commit 249a32b7eeb3edb6897dd38f89651a62163ac4ed upstream.

Based on USB2.0 Spec Section 11.12.5,

  "If a hub has per-port power switching and per-port current limiting,
  an over-current on one port may still cause the power on another port
  to fall below specific minimums. In this case, the affected port is
  placed in the Power-Off state and C_PORT_OVER_CURRENT is set for the
  port, but PORT_OVER_CURRENT is not set."

so let's check C_PORT_OVER_CURRENT too for over current condition.

Fixes: 08d1dec6f405 ("usb:hub set hub->change_bits when over-current happens")
Tested-by: Alessandro Antenucci <antenucci@korg.it>
Signed-off-by: Bin Liu <b-liu@ti.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/usb/core/hub.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1119,10 +1119,14 @@ static void hub_activate(struct usb_hub
 
 		if (!udev || udev->state == USB_STATE_NOTATTACHED) {
 			/* Tell khubd to disconnect the device or
-			 * check for a new connection
+			 * check for a new connection or over current condition.
+			 * Based on USB2.0 Spec Section 11.12.5,
+			 * C_PORT_OVER_CURRENT could be set while
+			 * PORT_OVER_CURRENT is not. So check for any of them.
 			 */
 			if (udev || (portstatus & USB_PORT_STAT_CONNECTION) ||
-			    (portstatus & USB_PORT_STAT_OVERCURRENT))
+			    (portstatus & USB_PORT_STAT_OVERCURRENT) ||
+			    (portchange & USB_PORT_STAT_C_OVERCURRENT))
 				set_bit(port1, hub->change_bits);
 
 		} else if (portstatus & USB_PORT_STAT_ENABLE) {