[BUG] Black screen 3 minutes after booting, CoffeeLake UHD 630

[zeroneplus2333]

Thank you very much，with your attached PNLF file and WEG, the black screen issue seems has been solved in my Dell G3 3579 (with i7-8750h UHD630), but when I try to reboot again and verify it, I encounter a kernel panic associated with "IONVME", I think I need to read Rehaman's thread, it seems that my toshiba nvme is not supported
Thank you again, and also thanks all the people who have worked for this problem!

 

[ShubhamSSJ]

Thanks you very much the new PNLF have completely resolve my issue, now 100% no more black screen
There is only a slight problem: every time I boot my computer the brightness is always at max.
My virtual nvram is working and the backlight level is saved in nvram, but it is not restored it seems.

Maybe the intermittent black screen issue is related to the brightness level being restored from NVRAM? When using RehabMan's PNLF and setting the brightness below 100% and rebooting results in a black screen for me but leaving it at 100% and it appears to work okay. Can anyone confirm this behavior?

I was trying to make my dedicated nvidia graphics work so I was using the emulated nvram.
It turned out that the emulated nvram was the cause for the brightness to be set at full while rebooting.
I switched to native nvram and now my brightness settings persists across boots.

Just one more thing to add - everytime I reboot from windows 10 to high sierra, I get black screen.
Cold boot always works fine.

 

[black.dragon74]

everytime I reboot from windows 10 to high sierra, I get black screen.

Hot booting a hackintosh is never recommended anyways.

 

[TheBerto]

I was trying to make my dedicated nvidia graphics work so I was using the emulated nvram.
It turned out that the emulated nvram was the cause for the brightness to be set at full while rebooting.
I switched to native nvram and now my brightness settings persists across boots.

Just one more thing to add - everytime I reboot from windows 10 to high sierra, I get black screen.
Cold boot always works fine.

If I remove EmuvariableEfi I get a kernel panic so I have to use virtual NVRAM.
Also before wathevergreen was updated to include AppleBacklightFixup.kext my brightness was correctly restored across reboot, I didn’t have the 3 minutes black screen but the max brightness was low.

 

[RehabMan]

The SSDT-PNLF in the hotpatch repo initializes the PWM_FREQ1 to 0xffff which is the root cause of this issue.

Thanks @Fraxul for pointing that out, I would never ever have guessed that.

@RehabMan, I would love to hear you views on this.

Credits: RehabMan for "graphics_PNLF-ACPI100.txt" DSDT patch. The attached SSDT is based on that code.

The fact that it initializes to 0xFFFF is by design.
If that is an issue, you will need to explain why.

If you want a basic PNLF, just use config.plist/ACPI/DSDT/Fixes/AddPNLF (no need for the various ACPI brightness methods, as macOS does not use them). Not sure what controls Clover offers for setting the _UID. You could also create a very simple PNLF device with the needed _UID (still no need for ACPI brightness methods).

Also, note that disabling SSDT-PNLF initialization of the backlight registers is part of the design... You can set RMCF.BKLT=0, but in that case you would need code to set _UID as appropriate.

 

[vettz500]

Some more testing on my end. If I remove the SSDT-PNLF from the patched folder, my laptop boots with full brightness every single time, no brightness controls obviously. As soon as I add Fraxul or RehabMan's SSDT-PNLF I immediately boot to a black screen almost every time.

I'm going to keep using it in this configuration and see what happens. I can deal with no brightness controls for the time being as long as the random kernel panics are gone.

Attached PR files without the SSDT-PNLF for reference, as well as whatevergreen debug log. Without SSDT-PNLF whatevergreen log is clean, no trampoline errors and CLFWriteRegister is being wrapped.

 

[RehabMan]

Some more testing on my end. If I remove the SSDT-PNLF from the patched folder, my laptop boots with full brightness every single time, no brightness controls obviously. As soon as I add Fraxul or RehabMan's SSDT-PNLF I immediately boot to a black screen almost every time.

I'm going to keep using it in this configuration and see what happens. I can deal with no brightness controls for the time being as long as the random kernel panics are gone.

Attached PR files without the SSDT-PNLF for reference, as well as whatevergreen debug log. Without SSDT-PNLF whatevergreen log is clean, no trampoline errors and CLFWriteRegister is being wrapped.

Try with basic PNLF that has correct _UID (no _INI code for fixing PWM setup).
You could also simply comment out the code that is setting up PWM.

 

[Amandeep]

Glad the issue is finally solved. It is fully working for me. No black screen issue. Backlight control working. Also, backlight level is being restored properly across reboots.

Don't have enough words to thank the awesome people who worked on it and fixed it.

 

[RehabMan]

Glad the issue is finally solved. It is fully working for me. No black screen issue. Backlight control working. Also, backlight level is being restored properly across reboots.

Nothing resolved until post #1 is re-written to contain completely tested/verified solution.

 

[Amandeep]

Nothing resolved until post #1 is re-written to contain completely tested/verified solution.

Right. I was just saying it is working for me. Let's just wait for a more stable fix which works for all and then this issue would be gone and post #1 rewritten to contain all the info needed on fixing this issue properly.