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LCD always 100% (ACPI/Auto Dim Brightness?!?)


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#1
spuck

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I noticed on my dell latitude d610, i cannot keep the LCD dimmed down, it always *gradually* goes back to 100% brightness, has anyone else experienced this? I keep reading about people having their screens dimming automatically, but mine does the opposite. During the day i don't notice or mind it, but at night, it's annoying always having a bright screen, plus I assume it drains the crap out of my battery!

I have a d610, Intel 915GM chip, running at 1400x1050.
Mac OS X version 10.4.5, with the ACPI PowerManagement extension hack installed (could this be it?!?)

It also does this very gradually, almost with the same pace your eye adjusts so you don't notice the difference, but i thought this was always done to make the LCD dimmer without the user noticing, is it a bug that makes my dell work the opposite?!?!

Thanks in advance, any help is gratefully appreciated!

Anyone?!?

#2
iratelizard

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Noticed this myself, I have a latitude d610. Any idea why?

#3
saschak

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Q35 does this too. removing kexts didint work.

#4
saschak

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After taking a look at the datasheet of the 945GM-Chipset, I found that pci-device 00:02.1 Register F4 (length: 1 Byte) is the backlight control register. At full brightness, its set to FF (255 dec) - on 00 its off.

On Linux I ran: setpci -s 00:02.1 F4.B=FF to set full brightness. 5A is the best value I guess.

I would try this on Mac but I havent found a version of setpci for mac.

Can someone point me out?

Sascha

#5
BlueD.Zhang

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sorry, wrong post.

Edited by BlueD.Zhang, 15 March 2007 - 04:41 AM.


#6
Daemon Lotos

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Hey there,

Having a similar problem myself... Well, let me rephrase... I *wish* I had your problem... My backlight won't engage... Well, that's a lie, when it's plugged in, there's a faint, and I mean FAINT glow from the bottom right hand corner. Unplug it, and presto... nadda.

Now, this happened to me with the JaS 10.4.7 installer disc, which prevented me from installing OS X at all on this laptop (couldn't see spit), until I grabbed the latest 10.4.8 SSE2/3 Combo Update, etc etc etc. from Demonoid. The installer worked just peachy, everything was visible, and happy.

And then I rebooted to OS X proper...

I've reinstalled from scratch, and repartitioned a few times, twiddling with the installation to see if it's something I've missed, but to no avail.

The *really* odd thing is, my gfx chipset is the Intel 945GM family. (Mobile, of course.) So if you can't turn yours down, how come I can't turn mine on? ^_^


I've pretty much given up busting my head over this one for the night. Just thought I'd see if anyone here had any suggestions. (I'm going to post this in a new thread as well, just posted here because you're using the same chipset as me it seems.)

Suggestions, or comments. (Or if anyone knows how to 'steal' the display config from the setup disc, that would work as well, I hope.)

Peace

#7
facio

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Try this: http://www.charcoald.../shades/details

:)

#8
ciper

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Try this: http://www.charcoald.../shades/details

:P



Shades does NOT adjust the backlight. His screen will still be at 100% brightness. Shades only hacks the "video out" to be darker.

#9
Daemon Lotos

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Or in my case, Shades won't turn my backlight on, it will only adjust the LCD image's brightness. Shades DOES NOT alter backlight level.

We've got the same hardware issue, only on different sides of the spectrum, someone has to know how to instruct the LCD backlight to turn on (or off)...

saschack found the registers you need to modify for this to happen, I just (personally) have no idea how to set these from within OS X, is this a kext hack issue, or is there another piece of software functionally similar to setpci (or pcitweak) for OS X. (I know X11 for Linux carries pcitweak, but I don't think the OS X release of X11 does.)

Anyone?

#10
BlueD.Zhang

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Or in my case, Shades won't turn my backlight on, it will only adjust the LCD image's brightness. Shades DOES NOT alter backlight level.

We've got the same hardware issue, only on different sides of the spectrum, someone has to know how to instruct the LCD backlight to turn on (or off)...

saschack found the registers you need to modify for this to happen, I just (personally) have no idea how to set these from within OS X, is this a kext hack issue, or is there another piece of software functionally similar to setpci (or pcitweak) for OS X. (I know X11 for Linux carries pcitweak, but I don't think the OS X release of X11 does.)

Anyone?


I've tried the setpci way and the acpi way. But no, they are useless. You can only change the value of the register, but the backlight is always 100%. By the way, I found the fn key changes the value too, so it's just the driver.

What happened, I don't know. Maybe np_ knows.

#11
dutty

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sorry for bumping this :thumbsup_anim:

but, this is the only thread on the entire board that contains useful information on that matter.

we know that the fn* keys actually change the value of the register but somehow it gets ignored.. my best guess is that the gma950 driver overrides the value or has a trap on that register and manually changes it back to max..
maybe we could have 2 different kexts and load which one we need, one for low/med brightness and one for fullbright.. or write a little kext hacker that hacks that kext and reload it..

i could write the tool if somebody could tell me the offset for the lcd brightness inside the gma950 driver.

edit: why i think the kext is responsible for this.. as long as the kext is not loaded the brightness can be changed using the fn keys (bootscreen or a removed appleintelgma950 driver)


btw, could a mod move this to hardware?

#12
wwweagle

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Dutty you are right and smart...Hope someone could go further in this way...

#13
wwweagle

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Any news on this topic?

#14
J_Zar

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It seems that this problem is widespread for every system with GMA 950.
Anyone can guess some useful trick? :)

#15
niko

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Hi, I need backlight control for my GMA950 Notebook too. Really badly:-)

So like other posters earlier I thought of two possible solutions:

Remove the AppleIntelGMA950* and AppleIntelIntegratedFrameBuffer.kext files from the Extensions folder.
This would let me control backlight with the function key, I have to sacrifice QE and CI though.
Also this doesn't let my do 1400x1050 on my Thinkpad T60 display (only 1280x1024). Does anyone know how to fix this and go full native resolution without the GMA950 drivers?

The other possibility would be to get a reverse engineered version of AppleIntelIntegratedFrameBuffer.kext and find the part that overwrites the backlight control register. But I dont know how to get the source of that kernel extension.

#16
J_Zar

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It seems that people from the hal linux project has already reverse engineered AppleIntelIntegratedFramebuffer.kext:

http
://lists.freedesktop.org/archives/hal-...ch/003131.html


But I can't find any other useful info till now...

#17
mac.nub

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On my Dell Inspiron 6400 /w GMA950 I can adjust the screen brightness by simply pressing the Fn + Up or Down arrow on my keyboard.

No idea if it's the same for any of you, but it's sure worth a try...

~mac.nub

#18
J_Zar

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Sorry, mac.nub, for me it does not work. In my laptop (Sony Vaio VGN-N21S) brightness buttons would be fn + F5 / F6, but they do not work. :D

#19
whice

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After taking a look at the datasheet of the 945GM-Chipset, I found that pci-device 00:02.1 Register F4 (length: 1 Byte) is the backlight control register. At full brightness, its set to FF (255 dec) - on 00 its off.

On Linux I ran: setpci -s 00:02.1 F4.B=FF to set full brightness. 5A is the best value I guess.

I would try this on Mac but I havent found a version of setpci for mac.

Can someone point me out?

Sascha

You can use Reggie SE from developer package. (CHUD).
I checked it. If you press buttons Fn+ F5 or Fn + F6 the state of register F4 is changing, but brightness isnot changing.
Any ideas?

#20
docmac

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You can use Reggie SE from developer package. (CHUD).
I checked it. If you press buttons Fn+ F5 or Fn + F6 the state of register F4 is changing, but brightness isnot changing.
Any ideas?


Any more news on this? I also have GMA 950 :(
I don't know how this has not been fixed :)

The only things that seem to be left to fix are:
1. intel 3945 wifi card
2. Headphone jack does not work
3. Brightness control

Is anyone working on these or will they never get fixed and stop talking about them?





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