[3.13.y-ckt stable] Patch "Input: usbtouchscreen - avoid unresponsive TSC-30 touch screen" has been added to staging queue

[Kamal Mostafa]

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

    Input: usbtouchscreen - avoid unresponsive TSC-30 touch screen

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt26.

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

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From b43d97134c2cdd57f8304c0b97e72851696c4a32 Mon Sep 17 00:00:00 2001
From: Bernhard Bender <bernhard.bender at bytecmed.com>
Date: Thu, 23 Jul 2015 13:58:08 -0700
Subject: Input: usbtouchscreen - avoid unresponsive TSC-30 touch screen

commit 968491709e5b1aaf429428814fff3d932fa90b60 upstream.

This patch fixes a problem in the usbtouchscreen driver for DMC TSC-30
touch screen.  Due to a missing delay between the RESET and SET_RATE
commands, the touch screen may become unresponsive during system startup or
driver loading.

According to the DMC documentation, a delay is needed after the RESET
command to allow the chip to complete its internal initialization. As this
delay is not guaranteed, we had a system where the touch screen
occasionally did not send any touch data. There was no other indication of
the problem.

The patch fixes the problem by adding a 150ms delay between the RESET and
SET_RATE commands.

Suggested-by: Jakob Mustafa <jakob.mustafa at bytecmed.com>
Signed-off-by: Bernhard Bender <bernhard.bender at bytecmed.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov at gmail.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/input/touchscreen/usbtouchscreen.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/input/touchscreen/usbtouchscreen.c b/drivers/input/touchscreen/usbtouchscreen.c
index 5f87bed..20aef5d 100644
--- a/drivers/input/touchscreen/usbtouchscreen.c
+++ b/drivers/input/touchscreen/usbtouchscreen.c
@@ -626,6 +626,9 @@ static int dmc_tsc10_init(struct usbtouch_usb *usbtouch)
 		goto err_out;
 	}

+	/* TSC-25 data sheet specifies a delay after the RESET command */
+	msleep(150);
+
 	/* set coordinate output rate */
 	buf[0] = buf[1] = 0xFF;
 	ret = usb_control_msg(dev, usb_rcvctrlpipe (dev, 0),
--
1.9.1