- a late-2013 15-inch MacBook Pro; no dGPU
- at work: two identical 1080p monitors. One connected via HDMI through a Belkin Thunderbolt 2 dock, another directly via HDMI
- at home: two identical 1680x1050 monitors. One connected via HDMI to DVI cable, another via mini-DisplayPort to DVI cable.
- 10.5.5 Beta (19F83c)
My work setup works fine.
But with my home setup, no matter which external monitor I connect first, as soon as I connect the second, I don't get a stable image. Instead, I mostly get three black screens, but every ~5 seconds, I briefly get either some or all of the displays briefly displaying an image; then it disappears again. Connect just one of the two, and it works fine.
It can't be bandwidth, because surely, 1680x1050 monitors take up less bandwidth than 1080p ones. I've also tried reducing one monitor's resolution before connecting the other, to no avail. It really feels more like one of them pesky Catalina issues.
- resetting the PRAM
- resetting the PMU
- deleting the
ByHostpreferences (which did contain many of the display setups)
- closing the lid so only the two externals are connected
Nothing can get both of those to show a stable image.