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[Guide] Patching DSDT/SSDT for LAPTOP backlight control

Joined
Apr 26, 2010
Messages
69
Motherboard
Asus Zenbook Pro UX501VW
CPU
Skylake i7-6700HQ
Graphics
Intel HD530 + GTX 960M
On my Skylake Asus, the brightness intensity keeps resetting after every reboot.

When I do nvram -p, I get:
Code:
intel-backlight-level    %80%02%00%00
security-mode    none
platform-uuid    %00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00
backlight-level    %80%02
SystemAudioVolume    /
SystemAudioVolumeDB    %12
LocationServicesEnabled    %01
csr-active-config    g%00%00%00
bluetoothActiveControllerInfo    o!\%0a%00%00%00%00%90%14%c4%8e%8f%fd0%12


The Method (RMCF) to retain brightness level doesn't seem to work. At least, not on Skylake.

Code:
        Device (PNLF)
            Name (_ADR, Zero)
            Name (_HID, EisaId ("APP0002"))
            Name (_CID, "backlight")
            Name (_UID, 10)
            Name (_STA, 0x0B)
            Method (RMCF)
            {
                Return(Package()
                {
                    "PWMMax", 0, // PWMMax of Zero uses BIOS PWM Max instead of OS X values
                    "Options", 0x01, // setting bit0 turns off smooth transitions
                })
            }
        }
 

RehabMan

Moderator
Joined
May 3, 2012
Messages
188,061
Motherboard
Intel DH67BL
CPU
i7-2600K
Graphics
HD 3000
Mac
  1. MacBook Air
Mobile Phone
  1. iOS
On my Skylake Asus, the brightness intensity keeps resetting after every reboot.

When I do nvram -p, I get:
Code:
intel-backlight-level    %80%02%00%00
security-mode    none
platform-uuid    %00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00
backlight-level    %80%02
SystemAudioVolume    /
SystemAudioVolumeDB    %12
LocationServicesEnabled    %01
csr-active-config    g%00%00%00
bluetoothActiveControllerInfo    o!\%0a%00%00%00%00%90%14%c4%8e%8f%fd0%12


The Method (RMCF) to retain brightness level doesn't seem to work. At least, not on Skylake.

Code:
        Device (PNLF)
            Name (_ADR, Zero)
            Name (_HID, EisaId ("APP0002"))
            Name (_CID, "backlight")
            Name (_UID, 10)
            Name (_STA, 0x0B)
            Method (RMCF)
            {
                Return(Package()
                {
                    "PWMMax", 0, // PWMMax of Zero uses BIOS PWM Max instead of OS X values
                    "Options", 0x01, // setting bit0 turns off smooth transitions
                })
            }
        }

RMCF has nothing to do with saving brightness level.

Test your NVRAM. You can set a variable with:
Code:
sudo nvram Test=This_is_a_test

Then reboot, and see if it is still there:
Code:
nvram Test

For most Sklyake computers, native UEFI NVRAM does not work so you must use EmuVariable+RC Scripts.
 
Joined
Apr 26, 2010
Messages
69
Motherboard
Asus Zenbook Pro UX501VW
CPU
Skylake i7-6700HQ
Graphics
Intel HD530 + GTX 960M
Unfortunately, the nvram test is not persistent after reboot.

Code:
nvram Test
nvram: Error getting variable - 'Test': (iokit/common) data was not found

Since the nvram test is not persistent, using EMUVariable + RC Scripts might not help.
 

RehabMan

Moderator
Joined
May 3, 2012
Messages
188,061
Motherboard
Intel DH67BL
CPU
i7-2600K
Graphics
HD 3000
Mac
  1. MacBook Air
Mobile Phone
  1. iOS
Unfortunately, the nvram test is not persistent after reboot.

Code:
nvram Test
nvram: Error getting variable - 'Test': (iokit/common) data was not found

Since the nvram test is not persistent, using EMUVariable + RC Scripts might not help.

EmuVariable + RC scripts is the fix.
 
Joined
Apr 26, 2010
Messages
69
Motherboard
Asus Zenbook Pro UX501VW
CPU
Skylake i7-6700HQ
Graphics
Intel HD530 + GTX 960M
Got it. Thanks.
 

RehabMan

Moderator
Joined
May 3, 2012
Messages
188,061
Motherboard
Intel DH67BL
CPU
i7-2600K
Graphics
HD 3000
Mac
  1. MacBook Air
Mobile Phone
  1. iOS
RehabMan,

Looking for the "brightness fix" patch. Was it removed from your directory?

https://github.com/RehabMan/Laptop-DSDT-Patch


Thanks

It is still there:

Screen Shot 2016-08-09 at 8.33.42 AM.png
 
Joined
May 8, 2016
Messages
48
Motherboard
Dell XPS 13, FD 9350
CPU
i5-6300u
Graphics
Intel HD 520
Mac
  1. iMac
^ Thanks. I just found it.


Which "brightness fix" should I use for Skylake integrated graphics Intel 520?


thanks again
 

RehabMan

Moderator
Joined
May 3, 2012
Messages
188,061
Motherboard
Intel DH67BL
CPU
i7-2600K
Graphics
HD 3000
Mac
  1. MacBook Air
Mobile Phone
  1. iOS
^ Thanks. I just found it.


Which "brightness fix" should I use for Skylake integrated graphics Intel 520?


thanks again

As per guide, post #1, use "Brightness Fix" and IntelBacklight.kext.
 
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