Touchpad testing.

[Mitch Bradley]

I agree with Ray. With my diagnostic, I can get reports from a Logitech
mouse at intervals of 5 ms or less.

See the attached. OLPCmouse is a Logitech PS/2 mouse in stream mode
attached to an OLPC board, EpiaMouse is the same mouse attached to an
EPIA board.

The diagnostic program is the same in both cases, as shown in red on the
pictures.

The "clear-queue many" part is crucial. It continually reads data from
the controller and discards it. Without that, both systems flow-control
the mouse quite aggressively, by holding the CLK line low for a long
time. The OLPC system holds it low for hundreds of milliseconds; the
EPIA board holds it low indefinitely, completely stalling the mouse
until you clear out the queue.




Ray.Tseng at quantatw.com wrote:
> Jim,
> 	Two possiblities:
> 	1)EC: as you mention EC slow down the rate
> 	2)BIOS: interrupt (serial IRQ) is not programmed correctly (Continuous or Quiet, level or edge,...) and the OS does not handle properly
> 	
> 	We are shooting 2nd.
>
> Ray Tseng 9/21/06 
>
> -----Original Message-----
> From: devel-bounces at laptop.org [mailto:devel-bounces at laptop.org] On Behalf Of Jim Gettys
> Sent: Thursday, September 21, 2006 3:48 AM
> To: Ray Tseng (曾文瑞); Zephaniah E. Hull
> Cc: OLPC Developer's List
> Subject: Touchpad testing.
>
> As suggested last night, we (Andres and I) took the older, 5V touch pad sample (the samples from early August; not the new 3.3 V touch pad we received in September) and plugged it into a standard PS/2 port on a conventional desktop.
>
> It behaves exactly as you might expect for normal operation: bursts of information are at regular 10ms intervals  on the oscilloscope (the default rate for PS/2 is supposed to be 100hz).
>
> Zephaniah reported that that older touch pad version on an unmodified (e.g. 5V) OLPC ATest board was also running very slowly, along with a standard PS/2 mouse.
>
> So unless Zephaniah managed to break the Linux kernel driver in some unique way, the theory that the EC is somehow slowing the rate down tremendously seems very likely.
>
> Zephaniah, does your kernel driver work well with a standard mouse on a conventional system.
>                                     Best regards,
>                                          - Jim Gettys
> --
> Jim Gettys
> One Laptop Per Child
>
>
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