Patchwork [52/74] USB: hub: handle claim of enabled remote wakeup after reset

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Submitter Herton Ronaldo Krzesinski
Date Jan. 24, 2013, 3:27 a.m.
Message ID <1358998046-613-53-git-send-email-herton.krzesinski@canonical.com>
Download mbox | patch
Permalink /patch/215165/
State New
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Comments

Herton Ronaldo Krzesinski - Jan. 24, 2013, 3:27 a.m.
3.5.7.4 -stable review patch.  If anyone has any objections, please let me know.

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

From: Oliver Neukum <oliver@neukum.org>

commit 07e72b95f5038cc82304b9a4a2eb7f9fc391ea68 upstream.

Some touchscreens have buggy firmware which claims
remote wakeup to be enabled after a reset. They nevertheless
crash if the feature is cleared by the host.
Add a check for reset resume before checking for
an enabled remote wakeup feature. On compliant
devices the feature must be cleared after a reset anyway.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
---
 drivers/usb/core/hub.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

Patch

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 2532bdc..92c0229 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2840,7 +2840,7 @@  int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
 static int finish_port_resume(struct usb_device *udev)
 {
 	int	status = 0;
-	u16	devstatus;
+	u16	devstatus = 0;
 
 	/* caller owns the udev device lock */
 	dev_dbg(&udev->dev, "%s\n",
@@ -2885,7 +2885,13 @@  static int finish_port_resume(struct usb_device *udev)
 	if (status) {
 		dev_dbg(&udev->dev, "gone after usb resume? status %d\n",
 				status);
-	} else if (udev->actconfig) {
+	/*
+	 * There are a few quirky devices which violate the standard
+	 * by claiming to have remote wakeup enabled after a reset,
+	 * which crash if the feature is cleared, hence check for
+	 * udev->reset_resume
+	 */
+	} else if (udev->actconfig && !udev->reset_resume) {
 		le16_to_cpus(&devstatus);
 		if (devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP)) {
 			status = usb_control_msg(udev,