[SOLVED]Black screen upon resume from suspend or hibernation

[PF4Public]

Hi there

I have a Dell Inspiron laptop with Gentoo. It has no trouble entering hibernation and suspend via gui or keyboard. It also restores normally. I have configured xfce4-power-manager to put it to sleep and hibernation with lid event. And here comes the most fascinating thing: it wakes up as if normal, but its screen is black. It is completely black, it is simply was not turned on upon waking up.

It looks like it is fine suspending and waking up from keyboard sleep button or via gui and in this case it properly switches the screen on, but with lid - it for some reason does not switch the screen on. Why is that happenning and how do I fix this?

I have tried making ACPI Video built-in, Brightness modules built in, tried completely disabling EFI FB from kernel, but nothing helps

vbetool does not solve this, but also breaks suspend and hibernation completely

[PF4Public]

Suddenly I have remembered that I once had genkernel kernel with initramfs, that probably worked fine.
It used the config from LiveCD, so I got that config and compiled the kernel with this config. Guess what? The issue was gone!
So I've got 2 configs, one of which works and the other does not. Firstly I thought it is because of initramfs, but it was really quick to recompile the working config without initramfs to be sure, that it is failing not because of initramfs. Next step was to diff the both configs and try to identify the setting, which affects my system. Well, easier said than done: diffing gave me overwhelmingly huge amount of differences to figure it out.
I had no other choice other than bit by bit morphing the working config into non-working, searching for the setting needed. It took quite a loooooot of tries, but eventually it was a success!
For anyone interested or the future person, non-working kernel was for some reason lacking `CONFIG_DRM_FBDEV_EMULATION=y`

[NTwoO]

Thanks for this information. This is most certainly handy. It is also known that the newer S0x sleep states tend to be a difficulty for the newer laptops.

[NTwoO]

I also had problems with an nvidia driver that was loaded even though I use the laptop with only the intel driver. Blacklisting the nvidia driver forced my PC to not load the driver and not cause problems with the load. My machine is a Dell Inspiron 7590. I doubt that I'll bother getting the nvidia running, since I basically use it only under Windows for the occasional game.