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Hi,
I got a Dell P2715Q UHD monitor which support DP 1.2 and HDMI 1.4.
My desktop hardware is:
1. CPU core i7-4790K (with HD 4600 integrated graphic card) From the manual, it's claimed that it's able to drive 3840*2160@60Hz for both HDMI and DP.
2. Motherboard Gigabyte G1 Z97 Sniper. the manual says it natively support HDMI 3840*2160@30Hz with HD4600. Well the DP support 3840*2160@60Hz. I don't quite understand what does 'natively' mean here ... does that mean I need to configure something to get DP to work for UHD?
The DE I'm using is XFCE.
So the problem is the following:
If I use HDMI, then the monitor can run at resolution is 3840*2160@30Hz (the lag is very noticeable) or 2560*1440@60Hz. Well, if I use DP, then the monitor is blank. Previously I tried a 1920*1200 monitor with DP, it had no problem.
Does anyone have an idea to get the DP work for UHD@60Hz? And have anyone successfully get a similar system work? I read many articles and none of them addressed this issue. Thanks a lot in advance!
Update 1:
Actually the system is able to use DP to run UHD@60Hz. But it's very unstable. The system blink once and then turns blank for about 10 seconds and repeat.
If I turn on the MST mode of the monitor, no-matter it's primary or secondary, the system can only run at UHD@30Hz. the secondary option is stable while the primary option is unstable, basically blink once every 3-5 seconds.
Update 2:
I checked the intel graphic driver and it's up to date. The module used for my card is i915. I also tried to use "cat /sys/class/drm/card0/error" to collect error and it shows no error.
Another observation of the problem is that the blink pattern seems to vary from boot to boot. Sometimes it's blank forever but sometimes it blinks.
Update 3:
It turned out the issue comes from the wire. After I changed to an Accell DP-mDP wire, the problem solved. And now my desktop run at UHD@60Hz. So I marked this problem solved.
Last edited by yubeic (2015-07-28 18:57:37)
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