From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932978AbaLBTVL (ORCPT ); Tue, 2 Dec 2014 14:21:11 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:46523 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932534AbaLBTVI (ORCPT ); Tue, 2 Dec 2014 14:21:08 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: =?UTF-8?q?Pali=20Roh=C3=A1r?= , Dmitry Torokhov , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 068/121] Input: alps - allow up to 2 invalid packets without resetting device Date: Tue, 2 Dec 2014 11:19:07 -0800 Message-Id: <1417548000-1794-69-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1417548000-1794-1-git-send-email-kamal@canonical.com> References: <1417548000-1794-1-git-send-email-kamal@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11-ckt12 -stable review patch. If anyone has any objections, please let me know. ------------------ From: =?UTF-8?q?Pali=20Roh=C3=A1r?= commit 9d720b34c0a432639252f63012e18b0507f5b432 upstream. On some Dell Latitude laptops ALPS device or Dell EC send one invalid byte in 6 bytes ALPS packet. In this case psmouse driver enter out of sync state. It looks like that all other bytes in packets are valid and also device working properly. So there is no need to do full device reset, just need to wait for byte which match condition for first byte (start of packet). Because ALPS packets are bigger (6 or 8 bytes) default limit is small. This patch increase number of invalid bytes to size of 2 ALPS packets which psmouse driver can drop before do full reset. Resetting ALPS devices take some time and when doing reset on some Dell laptops touchpad, trackstick and also keyboard do not respond. So it is better to do it only if really necessary. Signed-off-by: Pali Rohár Tested-by: Pali Rohár Reviewed-by: Hans de Goede Signed-off-by: Dmitry Torokhov Signed-off-by: Kamal Mostafa --- drivers/input/mouse/alps.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c index 80fac48..00544a6 100644 --- a/drivers/input/mouse/alps.c +++ b/drivers/input/mouse/alps.c @@ -2022,6 +2022,9 @@ int alps_init(struct psmouse *psmouse) /* We are having trouble resyncing ALPS touchpads so disable it for now */ psmouse->resync_time = 0; + /* Allow 2 invalid packets without resetting device */ + psmouse->resetafter = psmouse->pktsize * 2; + return 0; init_fail: -- 1.9.1