Path: csiph.com!goblin2!goblin.stu.neva.ru!aioe.org!bofh.it!news.nic.it!robomod From: Kamal Mostafa Newsgroups: linux.kernel Subject: [PATCH 3.19.y-ckt 044/130] Input: usbtouchscreen - avoid unresponsive TSC-30 touch screen Date: Fri, 28 Aug 2015 00:20:02 +0200 Message-ID: References: X-Original-To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com X-Mailer: git-send-email 1.9.1 X-Extended-Stable: 3.19 Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 52 Organization: linux.* mail to news gateway X-Original-Cc: Bernhard Bender , Dmitry Torokhov , Kamal Mostafa X-Original-Date: Thu, 27 Aug 2015 15:10:35 -0700 X-Original-Message-ID: <1440713521-5906-45-git-send-email-kamal@canonical.com> X-Original-References: <1440713521-5906-1-git-send-email-kamal@canonical.com> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1214861 3.19.8-ckt6 -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: Kamal Mostafa --- 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 a096633..c6f7e91 100644 --- a/drivers/input/touchscreen/usbtouchscreen.c +++ b/drivers/input/touchscreen/usbtouchscreen.c @@ -625,6 +625,9 @@ 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 -- 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/