Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265792AbUAKILB (ORCPT ); Sun, 11 Jan 2004 03:11:01 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265794AbUAKILB (ORCPT ); Sun, 11 Jan 2004 03:11:01 -0500 Received: from twilight.ucw.cz ([81.30.235.3]:2999 "EHLO twilight.ucw.cz") by vger.kernel.org with ESMTP id S265792AbUAKIK7 (ORCPT ); Sun, 11 Jan 2004 03:10:59 -0500 Date: Sun, 11 Jan 2004 09:10:46 +0100 From: Vojtech Pavlik To: Peter Berg Larsen Cc: Gunter =?iso-8859-1?Q?K=F6nigsmann?= , linux-kernel@vger.kernel.org Subject: Re: Synaptics Touchpad workaround for strange behavior after Sync loss (With Patch). Message-ID: <20040111081046.GA25497@ucw.cz> References: <20040109105855.GB9479@ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1799 Lines: 42 On Sat, Jan 10, 2004 at 11:50:02PM +0100, Peter Berg Larsen wrote: > On Fri, 9 Jan 2004, Vojtech Pavlik wrote: > > > The sync problems have so far been found to be caused by two possible > > causes: > > > > 1) Too long disabled interrupts. This is usually caused by ACPI > > BIOS, when some application is polling for battery status > > too often. > > > > 2) Incorrectly working timer (jiffies). This maybe caused by > > using the ACPI timer instead of the regular PIT one. Check > > the config. > > > > Both these causes break the lost bytes detection mechanism in the ps/2 > > code. It then thinks that a byte was lost (and thus the sync, too), but > > in reality everything is OK. This in turn causes two consecutive > > incorrectly parsed packets. > > I also believe some of the troubles comes from that we never check all > error codes from the mux: If mux is disabled for some reason all bytes are > stamped as timed out. The only way to recover is to reboot. And (I am > speculating here) if for some reason the mux believe the touchpad is > removed and connected the touchpad sends 2 bytes ack. > > I dont have a machine with active multiplexing so the the patch is > untested. It warns when the mouse is removed, and tries to recover > if multiplexing is disabled. It's nice, but er definitely shouldn't call i8042_enable_mux() from the interrupt handler, because i8042_command() waits for characters arriving in the interrupt handler, so we could get into rather nasty recursions. -- Vojtech Pavlik SuSE Labs, SuSE CR - 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/