Measurements: Massive Display-related power savings

Klaus Kurzmann mok at
Wed Oct 15 16:21:38 CEST 2008

* Michael 'Mickey' Lauer <mickey at> [081015 14:22]:
> Am Wednesday 15 October 2008 06:38:01 schrieb Mike (mwester):
> > > FSO should switch the backlight control from the sysfs method to the
> > > fbdev-ioctl method.  It's backwards compatible to old kernels (which will
> > > just backlight-blank) and future-compatible with kernels that add the
> > > jbt6k74 notifier and glamo fb_blank() patches.

> Already done, thanks to a patch from Harald and some refactoring.
> While doing this, I encountered a strange thing. One of my FreeRunners does 
> not recover from a BLANK ioctl anymore. The backlight turns on but the 
> display does not show any pixels. I have to reboot to make it work again. 
> Could that be connected to that infamous WSOD resume bug?
I think so. I get a WSoD on every resume, when suspended for more than a
minute. And since the frameworkd uses the new fb for blanking the screen
I get it on un-blanking as well.

If I comment out the changes in fb_notifier_callback (jbt6k74.c) the
WSoD goes away...

> Cheers,

> Mickey.


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