I think my last post disappeared - here it goes again:
@CaseySJ, I am hoping you might have some ideas on the following issue: whenever I sleep my displays (via Amphetamine or manually through the control+shift+eject shortcut), only
one will successfully wake, requiring a power cycle on the other one to be recognized. These are two LG 5k2k monitors connected to a single RX 580 via DisplayPort. I've tried adding back in darkwake=0 and tried switching from shikigva=16 to 80, but these produce no changes. I'm not coming up with much online, except maybe something having to do with framebuffer mismatch?
I also attempted to enable CSM support, but that inhibits successful boot (I am using your 0.6.4 OpenCore settings). What it does do is set identical signals do both displays (but the OS never loads).
Oh, and just another detail: it is the top DP port (furthest from the PCIe slot) that behaves 'nomally', and it is always the second port (next to the HDMI ports) that gets no signal after wake.
Edit: I put the RadeonBoost kext in and that essentially fixed it! There is always a sort of 'refresh' where the screens go black for a second after initially waking, but this is much better than the situation before. I'd love to hear you thoughts on what exactly is going on here