DisplayPort 1.2 support and daisy chain

[broz]

I've recently added a second display to my hackintosh build and wanted setup both display using daisy chaining

My box has a Gigabyte GTX 1070 Windforce, I'm using the Nvidia web drivers 378.05.05.15. OSX is Sierra 10.12.5.
The display is a Dell U2715H, second display is a Dell U2408WFP.

The monitor has an option to turn on Displayport 1.2 (and get MST with daisy chaining). If I boot with this option on, I get a black screen. Booting with this option off works ok, but no daisy chaining and no second display.

I've tested booting windows (same box) and everything is ok.

Seems the main problem is to get display port 1.2 working then try to see if MST is working.

Any ideas? Thanks

 

[MacPack]

It seems OS X artificially limits many display capabilities.

DisplayPort daisy chaining being one of them.

 

[Fl0r!an]

DisplayPort daisy chaining only (sort of..) works with AMD graphics, it's missing in all other graphics drivers. So there's not much you could do.

 

[broz]

Thank you guys.

So I tested this setup also with a MBP (Retina 13 Early 2015) and daisy chaining isn't working too, bummer

 

[Fl0r!an]

Yep, there's no difference for genuine Macs. Same set of drivers, same issues.

 

[rake.mistry]

DisplayPort daisy chaining only (sort of..) works with AMD graphics, it's missing in all other graphics drivers. So there's not much you could do.

Sorry to butt in, but what are the conditions on the "sort of" works with AMD? I have an RX 460 and would love to be able to daisy chain my 2 Dell U2515H's. Is it a matter of using a framebuffer?

 

[Fl0r!an]

On my old R9 280 it worked OOB (with RadeonFramebuffer as far as I remember), but it was quite buggy. E.g. dragging a window from one screen to the other usually resulted in graphical glitches.

Support for other AMD GPUs might vary, I don't know whether they've included the same kind of "half-baked" support for modern AMD GPUs.

 

[rake.mistry]

Ah, that's fair. My current setup works, so for the sake of having just one less cable coming out of my hack, I think I'll just leave it as-is for now. As nice as it would be to have, it seems like it's more hassle than it's worth for something that'll be buggy at best.

Thanks for letting me know, though! Cheers

 

[demboos]

Ah, that's fair. My current setup works, so for the sake of having just one less cable coming out of my hack, I think I'll just leave it as-is for now. As nice as it would be to have, it seems like it's more hassle than it's worth for something that'll be buggy at best.

Thanks for letting me know, though! Cheers

I decided to give daisy chaining a go, and so far, the results are positive. OSX 10.12.6, Radeon 7950 with 2 DP outputs, I have 3x Dell U21715H connected to it. Up to now I used two DP outputs + 1 HDMI to drive the third monitor, but today I tried connecting it through the DP output of one of the DP'connected monitors. Hotplug didn't work, but after an osx restart I got 3 separate desktops on each of the monitors!

So far I haven't seen any visual issues, but I'll test it a bit more (playing videos etc) + I'll test sleep behaviour too.

I would be really grateful if somebody could test this with RX4X0/RX5X0 and even Vega under osx 10.13.x.

Would be really cool to know what's the status of MST/daisychain for Nvidia Pascal with current drivers for osx 10.13.x.

I'm thinking of replacing my good old 7950 with sth newer, luckily all higher-end cards (radeon/nvidia) have 3 DP ports, so I don't have to rely on daisychain at all for my current needs.

 

[zakklol]

I just tried with my RX480 on osx 10.13.1.

Daisy chain works. Even worked as a hot plug. I daisy chained my two Dell U2414Hs, and got a mirrored display on the chained monitor. Remembered I'd disabled DP 1.2 a long time ago. Re-enabled it on the 'first' monitor and OSX then saw them both as separate displays.

This should make my cabling a bit less annoying!