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laptop screen not properly recognised, no brightness control.


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I have 10.11.2 running on my Elitebook 8570w. Lots of features work like sound, wifi, bluetooth, speedstep.


One thing is not though, Screen Brightness Control. This probably due to the fact my laptop screen isn't recognised. About this Mac shows a TV under Displays.


So how can I get the screen be recognised as a Applebacklightdisplay. I found out that some injections are needed, but which? And where and how to put them there. Can someone help me to solve mysteries? Maybe my assumptions are all wrong and the problem is somewhere else. Please correct me if I am wrong.

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Can you post your DSDT and extracted IOReg?


This may be due to missing or incorrect PNLF device attached to the discrete GPU in the DSDT. It can easily be added if required. It'll look something like this:

            Device (PNLF)
                Name (_ADR, Zero)  // _ADR: Address
                Name (_HID, EisaId ("APP0002"))  // _HID: Hardware ID
                Name (_CID, "backlight")  // _CID: Compatible ID
                Name (_UID, 0x0F)  // _UID: Unique ID
                Name (_STA, 0x0B)  // _STA: Status


You'll find details of a similar (but probably not entirely identical) situation here.

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Thanks for the quick response.


Because I am a beginner at hackintoshing it takes some time to post the files you ask for.


I probably need some tools to am I right? How do I get DSDT or do you need SSDTs too? How do I get such an ioreg file?


What does ioreg tell you? Do you need specific information about the laptop screen itself?


You probably need  info about where certain values are written?


How great is the risk to brick my current install? How do I attach the required files.


Many thanks in advance.

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Homework and studying required here...  ;-)


If you do not use an existing patched DSDT (DSDT.aml located in /Extra folder on Chameleon-based installations or in /EFI/CLOVER/ACPI/patched in Clover-based installations), you can extract it from BIOS with tools such as Chameleon Wizard, DSDTEditor or MacIASL. Look these up on the web to download them. From Windows, BIOS tables can be extracted using tools such as Aida64.


The IOReg is the collection of data related to the complete hardware arrangements of your computer. Difficult to grasp if you're not familiar with this or in the computer/IT domain. Download IORegistryExplorer off the web and save the output in a file.


To post attachments, use the "More Reply Options" at the bottom right corner of a post/reply area.

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Just curious:


where did you patch it with?


Can this patch also be applied in clover like an EFI string. Clover was installed and DSDT patches were made with Prebook Installer Clover Edition.

I like to learn from WHAT you have done and WHY. And also HOW it was done.


Do you expect brightness control will work after applying the patch?


Are the patches that were done in Prebook Installer still in place?


My patched DSDT already had the PNLF patch in.


The attached DSDT from you is exactly 1 Byte smaller than mine, so nothing seems to be added.

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I simply moved the PNLF device within the device PEGP.DGFX (for discrete GPU, i.e. the nVidia K1000M), but that may not work.


In this attached 2nd patch, I've added connector type 0x0200000 to 1st NVDA port, the one used for the LCD display, to try and declare it as such. Again, no guarantee.


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