backlight device, suspend/resume...

[Carsten Haitzler (The Rasterman)]

On Mon, 7 Jul 2008 23:34:05 +0200 "Michael 'Mickey' Lauer"
<mickey at openmoko.org> babbled:

> Am Montag 07 Juli 2008 12:21:11 schrieb Carsten Haitzler:
> > in:
> > /sys/devices/platform/s3c2440-i2c/i2c-adapter/i2c-0/0-0073/backlight/pcf506
> >33-bl
> >
> > ...
> > * backlight is ON and:
> > # cat bl_power
> > 0
> >
> > this seems reversed logic here. shouldn't 1 == on, 0 == off? the logic
> > seems to continue its inversness when u:
> 
> Been ranting about this for years now -- back then kernel developers decided 
> they want to have it that way and now we have to cope with it in userland.

oooh. a "design" decision... god help us. :( oh well. stuck with that.

> > * now resume (press power)
> > #cat brightness
> > 21
> > # cat actual_brightness
> > 63
> >
> > seems wrong to me. the brightness should be restored on resume exactly as
> > it was left.
> 
> Agreed.
> 
> > the same happens to bl_power. if it was off on suspend - it
> > should be off on resume (also i guess he inverse logic above fixed too).
> 
> Agreed (minus fixing the inverse logic, since this is a decision made by the 
> class device maintainers)

cool.

> > am i right? or am i missing something?
> >
> > also while i am at it...
> > /sys/devices/platform/neo1973-resume.0/resume_reason
> >
> > never seems it indicate the resume reason - no entry has an '*' next to it
> > ever... :(
> 
> D'oh, that's wrong.

yup. so i can never figure out what triggered the resume.. which heavily limits
my ability to sensibly handle things like "we resumed, but PLEASE leave the
screen off and backlight off on resume as the phone simply woke up to handle
some broadcast cell message and will want to head back to sleep really soon". i
have been wrestling with this over the past day or 2 to see what's up and just
can't get any more  info out of the kernel :( in addition to the above "bugs"
on resume with backlight... kind of makes it a blocker to improving
suspend/resume to "work as you'd expect".

> > are these known issues?
> 
> The bugtracker doesn't seem to know about it.

time to file some.

-- 
Carsten Haitzler (The Rasterman) <raster at openmoko.org>