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Thread: .Backlight driver


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Permlink Replies: 9 - Pages: 1 - Last Post: Nov 6, 2015 5:10 PM Last Post By: jduerstock
techknight

Posts: 110
Registered: 10/13/12
.Backlight driver
Posted: Dec 1, 2014 2:59 PM
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Can someone do me a favor? I need to see if someone will locate the .Backlight driver in the macintosh portable backlit model, and disassemble it for me. I need to take a peek at something.

Thanks.
bbraun


Posts: 493
Registered: 7/25/12
Re: .Backlight driver
Posted: Dec 1, 2014 9:24 PM   in response to: techknight in response to: techknight
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To completely disassemble a driver is a fairly time consuming activity, at least the way I was doing it with FDisasm. This isn't really something I can bang out real quick, so probably won't be getting to it. Maybe someone else can.
techknight

Posts: 110
Registered: 10/13/12
Re: .Backlight driver
Posted: Dec 2, 2014 3:19 PM   in response to: bbraun in response to: bbraun
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Booooo... I just needed to figure out how this driver worked at a hardware level. Was going to make myself a non backlit to backlit adapter.
uniserver


Posts: 53
Registered: 12/11/14
Re: .Backlight driver
Posted: Dec 11, 2014 5:07 PM   in response to: techknight in response to: techknight
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just install some LED's, KISS.
techknight

Posts: 110
Registered: 10/13/12
Re: .Backlight driver
Posted: Dec 13, 2014 6:10 PM   in response to: uniserver in response to: uniserver
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haha. Sure, i could do that, but thats not as fun.

I was going to take the panel apart, and replace the rear transflective sheet with an EL sheet, and inverter.

but I was wanting to tap into the backlit models driver, and be able to control the brightness the same way.
uniserver


Posts: 53
Registered: 12/11/14
Re: .Backlight driver
Posted: Dec 18, 2014 4:06 PM   in response to: techknight in response to: techknight
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I agree, it would be kind of cool to control the brightness :)
Arbee

Posts: 61
Registered: 11/29/12
Re: .Backlight driver
Posted: Jan 3, 2015 4:38 PM   in response to: uniserver in response to: uniserver
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The backlight is actually controlled by the M50753 PMU microcontroller. I'll see if I can find the backlight commands and see what exactly controls it, might be an on-board DAC or could be just a GPIO. The MacOS backlight driver just sends commands to the PMU.

Message was edited by: Arbee
techknight

Posts: 110
Registered: 10/13/12
Re: .Backlight driver
Posted: Jan 3, 2015 7:15 PM   in response to: Arbee in response to: Arbee
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I dont think this is entirely correct.

the screen contrast/brightness is. but not the backlight.....

I can swap PMUs between backlit/non backlit as I have in the past for repair reasons, and it doesnt matter.

you would think the non-backlit version wouldn't have the code in the PMU to run the backlight?
Arbee

Posts: 61
Registered: 11/29/12
Re: .Backlight driver
Posted: Jan 3, 2015 7:41 PM   in response to: techknight in response to: techknight
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My PMU dump from a non-backlit Portable (which I believe Rob did for me) exactly binary matches the dump from a PowerBook 100 (which is obviously backlit). My guess is the backlight was jettisoned from the Portable late as a cost-saving measure and then they put it back after consumer complaints.
jduerstock

Posts: 10
Registered: 6/30/13
Re: .Backlight driver
Posted: Nov 6, 2015 5:10 PM   in response to: techknight in response to: techknight
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Stumbled across this today: http://staticky.com/mirrors/ftp.apple.com/developer/Tool_Chest/OS_Utilities/Backlight_Control.sit.hqx
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