Updated to Catalina 10.15.4 Now External Monitor Has Problems

[ed.stein]

Same problem on 10.5.5, but I tried whatevergreen argument "igfxonln=1", and now auto detection is working!

Cool, I have the same problem. How do I do that?

 

[indade]

Just make boot argument in clover

 

[zappy39]

have same prob soon as I switch to HDMI. internal screen and external screen go off was working before last update 10.15.5

 

[carlosavilajr]

I just upgraded to Catalina 10.15.4 and also had the DisplayPort problem. Luckily I have 2 monitors hooked up to my Radeon RX 580, one DisplayPort (43" 4k), and the other HDMI (old 17" dell). I was dragging to figure it out, and then switch to SMBIOS 19,2 from 17,1 didn't fix the problem.

What did fix the problem was switching to MacPro6,1.

I now have all my hardware working again after the upgrade, including the new 2T PCIe 4 Sabrent NVMe.

seattlematt; You have no idea how much your post helped me, super hyper thanks a lot. when I updated to MacPro6,1. in clover voila!! all my 3 monitors started to work perfectly in Catalina 10.15.6 witn my Gigabyte Radeon RX 580 Gaming 8G thanks a lot man.
Just one Question what you mean when you said "2T PCIe 4 Sabrent NVMe".

 

[BoomR]

seattlematt; You have no idea how much your post helped me, super hyper thanks a lot. when I updated to MacPro6,1. in clover voila!! all my 3 monitors started to work perfectly in Catalina 10.15.6 witn my Gigabyte Radeon RX 580 Gaming 8G thanks a lot man.
Just one Question what you mean when you said "2T PCIe 4 Sabrent NVMe".

That's for the Sabrent m.2 NVMe solid-state drive... 2TB storage capacity, and the newest (Probably "Rocket" model) that supports PCIe v4 (which technically isn't supported yet because our CPUs aren't there yet-even though mobo supports it).