From: Vojtech Pavlik <vojtech@suse.cz>
To: Peter Berg Larsen <pebl@math.ku.dk>
Cc: "Gunter Königsmann" <gunter.koenigsmann@gmx.de>,
linux-kernel@vger.kernel.org
Subject: Re: Synaptics Touchpad workaround for strange behavior after Sync loss (With Patch).
Date: Sun, 11 Jan 2004 09:10:46 +0100 [thread overview]
Message-ID: <20040111081046.GA25497@ucw.cz> (raw)
In-Reply-To: <Pine.LNX.4.40.0401102336450.588-100000@shannon.math.ku.dk>
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
next prev parent reply other threads:[~2004-01-11 8:11 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-01-09 10:17 Synaptics Touchpad workaround for strange behavior after Sync loss (With Patch) Gunter Königsmann
2004-01-09 10:58 ` Vojtech Pavlik
2004-01-10 22:50 ` Peter Berg Larsen
2004-01-11 2:39 ` Peter Berg Larsen
2004-01-11 3:33 ` Dmitry Torokhov
2004-01-11 8:37 ` Gunter Königsmann
2004-01-11 12:52 ` Peter Berg Larsen
2004-01-11 14:22 ` Vojtech Pavlik
2004-01-11 15:34 ` Dmitry Torokhov
2004-01-11 15:06 ` Gunter Königsmann
2004-01-11 8:10 ` Vojtech Pavlik [this message]
2004-01-11 12:46 ` Peter Berg Larsen
2004-01-11 14:21 ` Vojtech Pavlik
2004-01-19 22:25 ` Vojtech Pavlik
2004-01-10 8:44 ` Dmitry Torokhov
2004-01-10 8:45 ` [PATCH 1/2] Synaptics rate switching Dmitry Torokhov
2004-01-10 8:46 ` [PATCH 2/2] Psmouse log and discard timed out bytes Dmitry Torokhov
2004-01-10 13:05 ` Gunter Königsmann
2004-01-10 13:23 ` Gunter Königsmann
2004-01-11 4:57 ` [PATCH 3/2] Psmouse log and discard timed out bytes - addition Dmitry Torokhov
2004-01-11 8:11 ` Gunter Königsmann
2004-01-10 9:56 ` [PATCH 1/2] Synaptics rate switching Vojtech Pavlik
2004-01-10 22:05 ` Gunter Königsmann
2004-01-10 23:37 ` Vojtech Pavlik
2004-01-11 2:20 ` Dmitry Torokhov
2004-01-11 8:00 ` Gunter Königsmann
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