[3.16.y-ckt stable] Patch "can: kvaser_usb: Retry the first bulk transfer on -ETIMEDOUT" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    can: kvaser_usb: Retry the first bulk transfer on -ETIMEDOUT

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt6.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 8944fd3f6f32286833402b7c6985a49940c812cf Mon Sep 17 00:00:00 2001
From: "Ahmed S. Darwish" <ahmed.darwish at valeo.com>
Date: Mon, 26 Jan 2015 07:24:06 +0200
Subject: can: kvaser_usb: Retry the first bulk transfer on -ETIMEDOUT

commit 14c10c2a1dd8eb8e00b750b521753260befa2789 upstream.

On some x86 laptops, plugging a Kvaser device again after an
unplug makes the firmware always ignore the very first command.
For such a case, provide some room for retries instead of
completely exiting the driver init code.

Signed-off-by: Ahmed S. Darwish <ahmed.darwish at valeo.com>
Signed-off-by: Marc Kleine-Budde <mkl at pengutronix.de>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/can/usb/kvaser_usb.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/usb/kvaser_usb.c b/drivers/net/can/usb/kvaser_usb.c
index 30067d464bd3..f85f02150877 100644
--- a/drivers/net/can/usb/kvaser_usb.c
+++ b/drivers/net/can/usb/kvaser_usb.c
@@ -1588,7 +1588,7 @@ static int kvaser_usb_probe(struct usb_interface *intf,
 {
 	struct kvaser_usb *dev;
 	int err = -ENOMEM;
-	int i;
+	int i, retry = 3;

 	dev = devm_kzalloc(&intf->dev, sizeof(*dev), GFP_KERNEL);
 	if (!dev)
@@ -1606,7 +1606,15 @@ static int kvaser_usb_probe(struct usb_interface *intf,

 	usb_set_intfdata(intf, dev);

-	err = kvaser_usb_get_software_info(dev);
+	/* On some x86 laptops, plugging a Kvaser device again after
+	 * an unplug makes the firmware always ignore the very first
+	 * command. For such a case, provide some room for retries
+	 * instead of completely exiting the driver.
+	 */
+	do {
+		err = kvaser_usb_get_software_info(dev);
+	} while (--retry && err == -ETIMEDOUT);
+
 	if (err) {
 		dev_err(&intf->dev,
 			"Cannot get software infos, error %d\n", err);
--
2.1.4