Messages in this thread | | | Date | Sun, 11 Jan 2004 09:10:46 +0100 | From | Vojtech Pavlik <> | Subject | Re: Synaptics Touchpad workaround for strange behavior after Sync loss (With Patch). |
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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/
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