#5575 HIGH Update.: Touchpad *mostly* non-functional

[Zarro Boogs per Child]

#5575: Touchpad *mostly* non-functional
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  Reporter:  Ozwald  |       Owner:  dilinger
      Type:  defect  |      Status:  new     
  Priority:  high    |   Milestone:  Update.1
 Component:  kernel  |     Version:          
Resolution:          |    Keywords:          
  Verified:  0       |    Blocking:          
 Blockedby:          |  
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Comment(by wvbailey):

 Symptom: G1G1 Touchpad is very sensitive in X-direction but only in center
 of pad; if you use a USB mouse to start pointer in dead center, Y-motion
 is smooth and seems calibrated to ends of touch-ad but any X-motion sends
 pointer to far left or far right (where Y-motion is okay).

 Experiments:

 *(1) Do 5 times: use optical mouse to position pointer at dead-center then
 do 4-finger salute. Result: 4 of 5 times no improvement. 1 time pad
 behaved like #2804 but after a minute or so "reverted" to #5575 (actually,
 this is the 2nd time I've had this happen).

 *(2) Put tin-foil over pad (held down with a christmas candle) and
 connected tinfoil to (presumably) system ground with a ball-clip connected
 to an audio jack plugged into the "mic" input; positioned pointer in
 center of screen with optical mas, then did 4-finger salute. No
 improvement.

 *(3a, b) Plastic lid over pad: No improvement. Paper over pad: No
 improvement

 *(4) Ceramic dish over pad: No movement at all. Only very light
 ''pressure+proximity'' causes motion. Pure pressure (with pencil eraser):
 no motion.

 *(5) aluminum foil over entire surface, either not grounded or grounded:
 reduces Y-axis sensitivity by a factor of about 5 and causes erratic
 Y-behavior; X-axis still very sensitive but now is harder to evoke the
 phenomenon.

 Conclusions: touchpad is very X-sensitive, but only in center of pad. No
 experiments were successful excepting (2) which seemed to invoke
 #2804-like behavior for a while.

 Conjectures:

 * All these touchpad issues are manifestations of the same problem.

 * Pad behaves as if there's an X-gain (sensitivity) that is about 10x-50x
 too high. This has the feeling of either (i) defective ALPS hardware, or
 (ii) a hardware implementation problem. More likely (ii) than (i). If the
 "code" is virtually the same for both X- and Y-, why would X-axis not work
 but Y-axis does work. If the code is the same from machine to machine then
 you'd expect the code to be faulty in all instances. Can the X- and Y-axes
 be flipped (in both hardware and software) to see if the problem goes with
 the axis?

 * Is there an ALPS interface-IC? If so, has the circuitry around it been
 implemented correctly -- any accidently-floating pins? Open etch? Bad IC?

 * Can someone direct me to a hardware spec sheet? thanks.

 * If you need another machine, I can return mine to you. Lemme know, Bill

-- 
Ticket URL: <http://dev.laptop.org/ticket/5575#comment:14>
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