There was some discussion about this bug on the linux.kernel.input group
a few months ago - see the link in comment #47.
There was an e-mail I did receive from Tommy Will which I thought was
also posted to the newsgroup, but apparently not, so I'm going to
include it here:
----
Sorry for wait a long time. I investigated this issue and with my
"Dell Latitude D630 + Dock + External Rushmore device" environment,
I can reproduce it with a very low rate.
"psmouse serio1: DualPoint TouchPad at isa0060/serio1/input0 lost sync
at byte 6" occurred after I continuously touch the
touchpad for more than 5 minutes.
However, it seems a bit difference from yours. Once my touchpad lost
sync, it will recover immediately and will not occur
until next 5 minutes. (From your mail, it seems much easier to reproduce)
After that, I tried to investigate with my low reproduce rate
environment. Here is what I have tried.
1) Log the raw data and locate why "lost sync" occurred.
I found that when "lost sync" occurred, it first received several
unknown packet that could not pass our packet valid logic. I asked
our H/W team member to check if it maybe our device's potential bug or
a hidden mode, but got the answer with "NO". Our F/W did not ever
design such packet format and they never saw that. (Please see my
attached picture)
2) In order to know where such weird packet comes, I used a tool to
capture the raw PS/2 data sent from touchpad. However, as long as
I connect the tool to debug, I can not reproduce the issue anymore : (
# I'm not familiar with H/W and have no idea why...
So, in a word, I still can not prove that this weird packet does not
come from our touchpad.
And here is my guess.
In laptop, there is a module called "EC". It's main for coordinate the
PS/2 data for both touchpad & keyboard. I'm now wondering if it's a
potential issue
of Linux EC driver for E7440. Under some situation, maybe EC will
forward wrong data to our input driver ?
If so, that will be help to explain why I can almost not reproduce it
on my side.
Finally, when I investigate this issue, I found some initialization
are no longer needed in latest Windows driver. Although I do not think
it's the root cause
of this time's issue, if it's lucky enough, it may have chance to
reduce the reproduce rate. Please have a try if you have time
----
On a sidenote, this problem seems to be worse on Ubuntu 14.04.
** Attachment added: "Attachment given with quoted email"
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1258837/+attachment/4131533/+files/LostSyncLog.png
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https://bugs.launchpad.net/bugs/1258837
Title:
[Dell Latitude E7440] ALPS touchpad keeps having state reset
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