Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966239AbcCPIJ4 (ORCPT ); Wed, 16 Mar 2016 04:09:56 -0400 Received: from mail.kernel.org ([198.145.29.136]:59698 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966203AbcCPIJd (ORCPT ); Wed, 16 Mar 2016 04:09:33 -0400 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Bernhard Bender , Dmitry Torokhov , Zefan Li Subject: [PATCH 3.4 043/107] Input: usbtouchscreen - avoid unresponsive TSC-30 touch screen Date: Wed, 16 Mar 2016 16:05:37 +0800 Message-Id: <1458115601-5762-43-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1458115541-5712-1-git-send-email-lizf@kernel.org> References: <1458115541-5712-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1690 Lines: 47 From: Bernhard Bender 3.4.111-rc1 review patch. If anyone has any objections, please let me know. ------------------ 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: Zefan Li --- 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 ce384a4..e57eaf8 100644 --- a/drivers/input/touchscreen/usbtouchscreen.c +++ b/drivers/input/touchscreen/usbtouchscreen.c @@ -586,6 +586,9 @@ 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