Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935115AbbHJKkF (ORCPT ); Mon, 10 Aug 2015 06:40:05 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43948 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933766AbbHJKQP (ORCPT ); Mon, 10 Aug 2015 06:16:15 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Jakob Mustafa" , "Dmitry Torokhov" , "Bernhard Bender" Date: Mon, 10 Aug 2015 12:12:31 +0200 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 102/110] Input: usbtouchscreen - avoid unresponsive TSC-30 touch screen In-Reply-To: X-SA-Exim-Connect-IP: 2.173.94.72 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1783 Lines: 48 3.2.71-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Bernhard Bender 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 Signed-off-by: Bernhard Bender Signed-off-by: Dmitry Torokhov Signed-off-by: Ben Hutchings --- drivers/input/touchscreen/usbtouchscreen.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/input/touchscreen/usbtouchscreen.c +++ b/drivers/input/touchscreen/usbtouchscreen.c @@ -528,6 +528,9 @@ static int dmc_tsc10_init(struct usbtouc 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), -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/