is it possible that you're using a cable that doesn't cover the 2.0 spec? Apparently that's a thing now.
Are the drivers just failing to install, or are they installing and then refusing to push 4k?
do you have error logs you can post?
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Two possibilities. Support isn't in yet because it's currently in the DAL patch which hasn't been accepted in kernel yet (probably 4.12, but you could enable it yourself by compiling the kernel).
Or the monitors specific weirdness hasn't been caught and patched yet.
There's a few bug reports around if you search for them.
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You should be spinning your own latest Mesa build drivers, like latest ones, or those from that community resource I can't remember.
Also rx480 isn't a 4k@60fps videocard for most things.
For the PRO to work in its latest version you need to update the kernel to over 4.8, either in Ubuntu or Mint.
I would propose to go for the Open Driver stack as the performance now is comparable to the PRO and it is improving with every version.
Use sth like ukuu to update to kernel 4.9 and then update to the latest MESA (dev) using this PPA:
https://launchpad.net/~paulo-miguel-dias/+archive/ubuntu/mesa
This would give you the best performance out of the card. Not sure of you get your 4K 60hz yet but it should get there as the driver and the kernel modules improves.
Of course if you want the stable version of MESA for less risk you can use this PPA first. It should give similar performance :
https://launchpad.net/~paulo-miguel-dias/+archive/ubuntu/pkppa/
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https://bugs.freedesktop.org/show_bug.cgi?id=98333
First thing that comes up. It may be dependent on the screen, but you can try with dal patches
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They just refuse to push 4k 60. when i use xrandr its not a available mode. and wont allow me to set refresh higher then 24hz. Also 4k 60hz works fine under windows so I don't think it's the cable. (have confirmed with ufotest)
so you get 4k but only 24hz? what driver version are you trying to use?
Thats correct. When I just attempted to add a new mode to xrandr and it dropped the screen until i changed it back and did a reboot
Some modes with incorrect/incompatible hsync and vsync settings might cause that. Test these settings (replace DP4 with you output port):
xrandr --newmode "3840x2160_60" 534.010 3840 3982 4027 4064 2160 2170 2180 2190 +hsync +vsync
xrandr --addmode DP4 3840x2160_60
xrandr --output DP4 --mode 3840x2160_60Use also cvt program to test other settings.
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As tkoham suggested. What cable are you using and do you have another cable to try. 4K@60Hz is the limit on the cable and a crappy cable my fall back to a lower speed.
Hey, this worked.
Unfortunately the screen flickers now at 4k 60Hz which makes it unusable.
Using an RX480 connected to 4k tv via hdmi2.0 and amdgpu-pro driver on ubuntu 16.04
In case it helps anybody, 50Hz is stable for me at 3840x2160.
This is what i used to enable it:
xrandr --newmode "3840x2160_50" 445.008 3840 3982 4027 4064 2160 2170 2180 2190 +hsync +vsync && xrandr --addmode HDMI-A-0 3840x2160_50 && xrandr --output HDMI-A-0 --mode 3840x2160_50
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FTFY.
The commands I mentioned were required when I needed to use 60hz on intel and nvidia graphics. I finally tested this weekend with amdgpu and ended with similar result with yours when using hdmi.
However when using displayport with club-3d displayport to hdmi adapter it worked flawlessly, I didn't even had to run those commands as it detected 60hz automatically.
I'm using archlinux with 4.10 kernel with all packages updated, a samsung 40ku6000 tv and a msi gaming x rx480 to test this.
With the new 17.10 amdgpu driver, 60Hz @ 4k over HDMI works flawlessly for me. There's no screen flicker like I had running the 16.40 driver.
You do still have to manually create the new mode with xrandr though.
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I’m having the same issue on my RX460 on Fedora 26. 4k@60Hz works fine over DP but not over HDMI (despite the fact that it works in Windows). I’ve tried compiling amd’s latest staging downstream kernel but it doesn’t seem to affect anything. I don’t think using AMDGPU-PRO is an option either since i’m on Fedora.
here is how i did it somewhat
Hi there, I have Xubuntu 16.04 and the amdgpu pro driver version 17.30 installed on my PC with a RX 460 Radeon graphics card . 4k30 works always on it. 4k60 worked but only when I switched from 30 Hz to 60 Hz and back multiple times until with some luck the connection succeeded. This was a weird random behavior when setting up the HDMI connection. Now I have bought an HDMI switch and 4k60 is no longer working 
It’s not a problem of the switch because Playstation 4 Pro works fine with it.
Recently a very interesting long German article on the page www.golem.de explained the authors findings with 4K and HDR monitor setups with Apple TV, Linux and Windows. They explained they only got 60 Hz at 4K when using a certified HDMI 2.0 cable. The non certified ones even marked as 2.0 only made 30 Hz available. My personal findings can be found here. Like the people on golem.de I also had to activate HDMI Deep Color. It would be interesting to see if the random behaviour I described above would disappear whith certified HDMI cables. I’ll report any new findings when Ubuntu 18.04 is available with the new AMD display code (DC). If it will not work I’ll try it with certified cables.
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I tested my setup now with certified hdmi 2.0 cables. Unfortunately I saw no differences and I still have the same problems.