HP Elitebook 8460p - Backlight Control Issue

[michaeldim]

I've installed OS X 10.10 Yosemite onto my 8460p according to the stickied Clover guide, using the Probook Installer.

Unfortunately, because I like to make things difficult, I have the 8460p with the AMD discreet GPU and the 1600x900 panel.

Everything went swimmingly during install, the Probook Installer took care of everything, and I used the EDID fix to eliminate the color banding issue.

It seems I do not have control of the backlight.

Initially, OS X did not register the backlight at all; there was no slider available in System Preferences, and no response from the backlight keys. (Other hotkeys, ie volume control, do work)

I tried to install RehabMan's ACPIBacklight.kext. That caused the brightness slider to appear (both in System Preferences and in response to pressing the brightness keys) However, changing the setting does not effect the screen brightness in any way. It is always at its maximum setting.

I've crawled around the forum a bit looking for some help, but it seems few people have the same arrangement as I do. I realize that support for the AMD card is experimental, and that a solution may not even be available. However, I thought I'd ask just in case.

Thanks again for all the hard work that made this possible.

 

[RehabMan]

I've installed OS X 10.10 Yosemite onto my 8460p according to the stickied Clover guide, using the Probook Installer.

Unfortunately, because I like to make things difficult, I have the 8460p with the AMD discreet GPU and the 1600x900 panel.

Everything went swimmingly during install, the Probook Installer took care of everything, and I used the EDID fix to eliminate the color banding issue.

It seems I do not have control of the backlight.

Initially, OS X did not register the backlight at all; there was no slider available in System Preferences, and no response from the backlight keys. (Other hotkeys, ie volume control, do work)

I tried to install RehabMan's ACPIBacklight.kext. That caused the brightness slider to appear (both in System Preferences and in response to pressing the brightness keys) However, changing the setting does not effect the screen brightness in any way. It is always at its maximum setting.

I've crawled around the forum a bit looking for some help, but it seems few people have the same arrangement as I do. I realize that support for the AMD card is experimental, and that a solution may not even be available. However, I thought I'd ask just in case.

Thanks again for all the hard work that made this possible.

Download patchmatic: https://bitbucket.org/RehabMan/os-x-maciasl-patchmatic/downloads/RehabMan-patchmatic-2015-0107.zip
Extract the 'patchmatic' binary from the ZIP. Copy it to /usr/bin, such that you have the binary at /usr/bin/patchmatic.

In terminal,

if [ -d ~/Downloads/RehabMan ]; then rm -R ~/Downloads/RehabMan; fi
mkdir ~/Downloads/RehabMan
cd ~/Downloads/RehabMan
patchmatic -extract

Note: It is easier if you use copy/paste instead of typing the commands manually.

Post contents of Downloads/RehabMan directory (as ZIP).

Also, post ioreg: http://www.tonymacx86.com/audio/58368-guide-how-make-copy-ioreg.html. Please, use the IORegistryExplorer v2.1 attached to the post! DO NOT reply with an ioreg from any other version of IORegistryExplorer.app.

And output from:

kextstat|grep -y acpiplat
kextstat|grep -y appleintelcpu
kextstat|grep -y applelpc

Also, post EFI/Clover folder.

 

[michaeldim]

I have gather the 4 pieces of info you requested

This zip contains the Patchmatic output, the IOReg, the kextstat output, and the Clover folder from the EFI partition.

 

[RehabMan]

I have gather the 4 pieces of info you requested

This zip contains the Patchmatic output, the IOReg, the kextstat output, and the Clover folder from the EFI partition.

Remove ACPIBacklight.kext, rebuild caches, reboot, test.

 

[michaeldim]

I removed ACPIBacklight.kext from S/L/E, rebuilt the cache, and rebooted. There seems to be no change in behavior, the backlight slider is still present, but has no effect. The keys do the same.

 

[RehabMan]

I removed ACPIBacklight.kext from S/L/E, rebuilt the cache, and rebooted. There seems to be no change in behavior, the backlight slider is still present, but has no effect. The keys do the same.

Download patchmatic: https://bitbucket.org/RehabMan/os-x-maciasl-patchmatic/downloads/RehabMan-patchmatic-2015-0107.zip
Extract the 'patchmatic' binary from the ZIP. Copy it to /usr/bin, such that you have the binary at /usr/bin/patchmatic.

In terminal,

if [ -d ~/Downloads/RehabMan ]; then rm -R ~/Downloads/RehabMan; fi
mkdir ~/Downloads/RehabMan
cd ~/Downloads/RehabMan
patchmatic -extract

Note: It is easier if you use copy/paste instead of typing the commands manually.

Post contents of Downloads/RehabMan directory (as ZIP).

Also, post ioreg: http://www.tonymacx86.com/audio/58368-guide-how-make-copy-ioreg.html. Please, use the IORegistryExplorer v2.1 attached to the post! DO NOT reply with an ioreg from any other version of IORegistryExplorer.app.

 

[michaeldim]

I've already done so, but I did it again, and here is the output.

 

[RehabMan]

I've already done so, but I did it again, and here is the output.

This is where I verify you did what was requested. You did not...

ACPIBacklight.kext is still installed. Read post #4.

 

[michaeldim]

You're right, I followed an incorrect procedure for removing the Kext.

I believe that I have now succeeded in removing the Kext, and behavior has reverted back to the way it was before, where no brightness slider is present, and the keys have no effect.

Attached is a copy of the IOreg and patchmatic output from after the removal for your review.

 

[RehabMan]

You're right, I followed an incorrect procedure for removing the Kext.

I believe that I have now succeeded in removing the Kext, and behavior has reverted back to the way it was before, where no brightness slider is present, and the keys have no effect.

Attached is a copy of the IOreg and patchmatic output from after the removal for your review.

Your ioreg still shows ACPIBacklight.kext installed.

This ioreg was captured with ACPIBacklight.kext installed and backlight slider in SysPrefs->Displays present.