Skylake (i5-6600) DP 1.2 woes

[Vyrlokar]

Hello everyone

I'm building a new linux system for office/development use, with the following specs

CPU: Intel i5-6600
Motherboard: Asus Z170-A
Monitors: 2? Dell U2515H (2560?1440)
OS: Xubuntu 15.10

Since the system would not be used for gaming (for now), I decided against purchasing a dedicated GPU (plus I'm waiting for AMDGPU to mature). The idea was to take advantage of DP 1.2 MST to daisy chain the monitors to the iGPU, since the motherboard has only a single Display Port. The problem is that when setting the monitor to DP 1.2 mode (Dell monitors work in DP 1.1 mode by default), the monitor got no signal and entered power saving mode. The monitor worked perfectly in DP 1.1 mode without daisy chaining the second monitor.

I tried installing kernel 4.3 and 4.3-drm-intel-next, since I read here that you need kernel 4.3 for proper Skylake support, and updated my drivers with the padoka ppa, but the result was the same, and in no case did I get useful info in Xorg.log (nor in other log files) on the issue. Connecting a third monitor to the motherboard VGA port let me execute xrandr -q, and find that the monitors were correctly detected at DP1-1 and DP1-8 (with proper resolutions and refresh rates). I have yet to try using an HDMI cable to see if I can get the second monitor working, but I would prefer having everything work over DisplayPort.

[Vyrlokar]

Well, in the end I reverted to stock mesa (I was getting visual artifacts with the latest code), and bought a 3.5? HDMI cable. I'll still look forward to see if MST support becomes usable under FLOSS drivers

[Kano]

Ubuntu backported Intel DRM from 4.3, therefore you could not see a difference. Did you ask in irc://irc.freenode.net/#intel-gfx yet?

[Vyrlokar]

Ubuntu backported Intel DRM from 4.3, therefore you could not see a difference. Did you ask in irc://irc.freenode.net/#intel-gfx yet?

Nope, I did not know about it (part of the reason I asked here was to get some pointers to the appropriate way to contact the devs). I've searched the bugtracker though, and the issue has been reported, though I can't find it today. Will take a look at freenode though.

EDIT: What's the proper netiquette to use the IRC channel? It's a moderated channel, but I don't want to randomly start sending private messages to everyone