[PATCH] [JBT6K74] add framebuffer blanking notifier

Andy Green andy at openmoko.com
Wed Oct 8 13:57:28 CEST 2008

Hash: SHA1

Somebody in the thread at some point said:

|> The only thing I guess to be aware of is that this is disconnected from
|> /sys control of backlight device status unless I missed a point
|> somewhere, it means that framebuffer blanking is now better for power
|> than turning down backlight by /sys and should be preferred.
| What does that mean for userland? AFAICT echo "1"
|> /sys/class/backlight/whatever/bl_power should give the maximum power
| savings -- no?

No, backlight is looking after backlight only, which is strictly a PMU
regulator action; whereas framebuffer blanking is an opportunity to
coordinate multiple areas.

Harald's larger concept is that under the umbrella of the framebuffer
blanking, we not only use the existing connection to control of
backlight there to take that down, but we take the opportunity to turn
off other video related circuitry (ie, Glamo) which is otherwise still
blaring away into the dark LCM.

- -Andy
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