[Techteam] Heads up on touchpad change

[pgf at laptop.org]

andres wrote:
 > > 
 > > Cc'ing devel for a wider audience.  Basically, we've got a new
 > > touchpad driver that uses mouse mode rather than advanced/stream
 > > mode.  This means the PT won't work, but the benefits are numerous:
 > > 
 > >  - lots of silly complexity ripped out of the driver
 > >  - smaller packet size means that deltas between packets are much much
 > > smaller
 > >  - smaller deltas means that it's much easier to detect jumpiness; i
 > > found it impossible to get >90px deltas using my fingers, but i saw
 > > 150px deltas when the touchpad was freaking out
 > 
 > This is one of the hardware bugs that we see; when cursor gets jumpy.
 > When one puts their finger down on the pad, the cursor will make a huge
 > jump across the screen.  This is now fairly easy to detect; we can't
 > stop it, but once we've detected it, we can trigger a recalibration.

fyi, i'm running 2.6.22-20080710.1 -- the backport kernel that
deepak put together -- on 656.

i'm seeing this in the logs fairly frequently:
Jul 14 11:57:26 creeper kernel: [44706.909058] psmouse serio1: >100px jump detected (-130,1)
Jul 14 12:10:05 creeper kernel: [45465.974069] psmouse serio1: >100px jump detected (3,-150)
Jul 14 12:10:10 creeper kernel: [45470.887243] psmouse.c: HGPK at isa0060/serio1/input0 lost synchronization, throwing 2 bytes away.
Jul 14 12:10:10 creeper kernel: [45470.907683] psmouse.c: resync failed, issuing reconnect request
Jul 14 12:10:22 creeper kernel: [45482.938494] psmouse.c: HGPK at isa0060/serio1/input0 lost synchronization, throwing 1 bytes away.
Jul 14 12:10:22 creeper kernel: [45482.953512] psmouse.c: resync failed, issuing reconnect request
Jul 14 12:21:41 creeper kernel: [46161.407663] psmouse.c: HGPK at isa0060/serio1/input0 lost synchronization, throwing 2 bytes away.
Jul 14 12:21:41 creeper kernel: [46161.425724] psmouse.c: resync failed, issuing reconnect request
Jul 14 12:21:56 creeper kernel: [46176.349552] psmouse serio1: >100px jump detected (-196,-32)
Jul 14 12:38:38 creeper kernel: [47178.646397] psmouse serio1: >100px jump detected (-108,71)

as far as i can tell, these always occur while i'm using the touchpad.

 > 
 > What an end user will see:
 > 
 > They will be
 > using the touchpad (although that's not a requirement, and detection
 > should occur correctly regardless of whether the pad is actually in
 > use), and suddenly the cursor will start misbehaving.  After anywhere
 > from 5s to 60s or of it misbehaving (the worse it behaves, the quicker
 > the driver will catch it), the driver should trigger a recalibrate.  At
 > that point, the cursor will simply vary between unresponsive, and jumpy.
 > That will be the case until the user removes their hands from the pad
 > for 3s (either they've managed to finally click on what they wanted to
 > click on, and are typing something, or they've turned away from the
 > machine for a second, or they're just used to this occurring and they
 > know to wait). After the touchpad has been clear for 3s, the cursor
 > should go back to normal. Note that 3s is a cautious number; we can

if you think we should be experimenting, can you list here the
tuneables we should be trying for both the ">100px" jump behavior
above, and the "3s" delay?

if the unusable period remains appreciable, and the recals remain
frequent, we should seriously consider visible feedback of some
sort to make it clear what's going on.  (it's even taking me a
while to remember that when the cursor goes wonky to "let go"
rather than continue to try and control it -- and i (in theory)
know what's going on.)

finally:  which is the correct current trac # for the touchpad issue(s)?

paul
=---------------------
 paul fox, pgf at laptop.org