ACPIBacklight.kext control

[duraaraa]

Hello.

I have a thinkpad W520 which allows switching between discrete nvidia graphics and integrated intel graphics. Unfortunately, ACPIBacklight.kext works great with Intel, but loading it while using nvidia makes brightness setting impossible.

I'm using clover and hoping someone, maybe rehab man, could help me sort this problem out.

Seeing as that I'm using clover...
I'd like to be able to dynamically load or not load ACPIBacklight.kext based on my config.plist file, or somehow modify it to only load if the intel graphics are present. Any idea of how that would be possible?

 

[RehabMan]

Hello.

I have a thinkpad W520 which allows switching between discrete nvidia graphics and integrated intel graphics. Unfortunately, ACPIBacklight.kext works great with Intel, but loading it while using nvidia makes brightness setting impossible.

ACPIBacklight.kext can work with nvidia, but you'd have to implement the correct DSDT patches appropriate for the hardware. The DSDT patches in my repo are strictly for the Intel hardware for PWM backlight control.

Seeing as that I'm using clover...
I'd like to be able to dynamically load or not load ACPIBacklight.kext based on my config.plist file, or somehow modify it to only load if the intel graphics are present. Any idea of how that would be possible?

Not possible as far as I know. If you figure out what to do in your ACPI backlight methods, they could automatically do the right thing.

 

[duraaraa]

ACPIBacklight.kext can work with nvidia, but you'd have to implement the correct DSDT patches appropriate for the hardware. The DSDT patches in my repo are strictly for the Intel hardware for PWM backlight control.

Do you know of any samples of the DSDT patches for that? I have backlight control working with the regular _DSM method of the video card, and with the 'generic' PNLF. Using ACPIBacklight.kext lets me control the backlight in terms of giving me the slider, but the backlight stays 100% regardless.

Obviously, not using it, the backlight controls work fine, although with a lesser range than I would like.

Not possible as far as I know. If you figure out what to do in your ACPI backlight methods, they could automatically do the right thing.

I'm thinking along the lines of blocking the kext in the clover config, but I have tried putting ACPIBacklight as the kext to block, and it doesn't seem to work, so that's where I am stuck.

For now, I'm just not using it, but if you really do know of a way to get it to work with nvidia, a sample or more details about what exactly has to be implemented would be super helpful!

 

[RehabMan]

Do you know of any samples of the DSDT patches for that? I have backlight control working with the regular _DSM method of the video card, and with the 'generic' PNLF. Using ACPIBacklight.kext lets me control the backlight in terms of giving me the slider, but the backlight stays 100% regardless.

Not sure what you mean "_DSM method of the video card"...

If you have backlight control working with ACPIBacklight and the OEM provided _BCL/_BCM/_BQC methods, then have your DSDT automatically switch between using the Intel methods (my patch) and the OEM methods.

I don't know of any samples of hardware control of nvidia backlight. Of course, I haven't really looked either, given that I don't have the hardware (no motivation to spend hours googling...)