Re: [ECOS] odd serial input bug in redboot 095308 20010607 on iP

[Gary Thomas <gthomas at cambridge dot redhat dot com>]

On 08-Jun-2001 David Bliss wrote:
> On Fri, Jun 08, 2001 at 09:02:51AM -0600, Gary Thomas wrote:
>> 
>> I've never seen this and I _have_ put RedBoot on a number of iPAQ units.
>> Which is not to say, "I don't believe you".
>> 
>> What happens if you press the reset button (small indent on the bottom 
>> of the unit)?
> 
> Same behaviour as 'reset'.  If it was previously working, it continues to
> work.  If it was previously not working it continues to not work.
> 

That pretty much kills the speculation below.

Have you changed the baud rate, or is it still at the default of 38400?

Do you see any of the boot-up messages on the serial port when it freezes?  These
should be displayed, no matter what, up to the first prompt.

I do have a unit here where the serial is pretty squirrely, although not the
same as yours.  I've found that if I simply unplug/plug the serial (take it out
of the cradle, whatever), that it comes back fine.  Can you try this?

Do you have a network connection?  If so, you could try accessing the unit that
way when it is in this state and maybe get a glimpse into what it is doig.

What is the vintage of this unit?

>> The most likely cause is that when powered on cold, on your unit, the keypad
>> or the touch screen are presenting some events.  This will be interpreted by
>> RedBoot as an attempt to use the keypad/touchscreen for input and activity
>> on the serial port will cease.  Remember that RedBoot tries to use any available
>> I/O device when first booted and then "settles" for the first one that actually
>> gets any input.
> 
> Possible, but on first touchscreen input, the screen 'blinks' in the same
> way that it did when settling on an input device (whether screen or touchpad)
> when running from WinCE.
> 
>> As an experiment, you could try installing a version which subverts this
>> behaviour.  We could also try to learn what's coming in from where (keypad
>> or touch screen) to see what's up here.
> 
> I'd be glad to do so if you'll assist me in locating/preparing such an image
>:)
> 
> Thanks,
> david