Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2993439AbbHHW1J (ORCPT ); Sat, 8 Aug 2015 18:27:09 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:36514 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2993574AbbHHWSM (ORCPT ); Sat, 8 Aug 2015 18:18:12 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jakob Mustafa , Bernhard Bender , Dmitry Torokhov Subject: [PATCH 4.1 077/123] Input: usbtouchscreen - avoid unresponsive TSC-30 touch screen Date: Sat, 8 Aug 2015 15:09:15 -0700 Message-Id: <20150808220720.478940068@linuxfoundation.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <20150808220717.771230091@linuxfoundation.org> References: <20150808220717.771230091@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1800 Lines: 50 4.1-stable 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: Greg Kroah-Hartman --- drivers/input/touchscreen/usbtouchscreen.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/input/touchscreen/usbtouchscreen.c +++ b/drivers/input/touchscreen/usbtouchscreen.c @@ -627,6 +627,9 @@ 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/