minidp and hdmi double 4k output flicker

[bjgowlk]

single 4k is perfect, but when I connect two 4k moniters(dell 2718q) via miniDP and HDMI, two screens are flikering when I move my mouse, wish sombody could help!

[bjgowlk]

Does anybody meet the same problem?

[kennymustdie]

Hi, i have not double 4k at the moment. One 4k on DP and a 2K on HDMI. I have in some Resolution the same Prolbem. If i choose the resoluition in "lower Quality" it works. To get there hold the alt key wenn you klick on the resoluiton field in Diplsy Settings.

[psychic69]

I am using 2 LG 4K displays (tried freesync on and off) both in DP ports, when I plug in the second, the screen flickering is active. I can say if I put lower resolution settings that the flickering goes away however since these are not native resolution the text is fuzzy and interpolated. Please examine this dual 4K monitor issue. Thanks

[ccsnake]

I have same problem.

[KrisCris]

Same problem. Not even necessarily need dual 4k displays to trigger this issue, like mine is 4k + 2k..

[Yrp]

Same problem. one is p2715Q, another is u3219Q, Only one is perfect. But two is plugged in miniDP ports, the both screen begin flicker.

[psychic69]

I reduced the resolution using hidden alt modes, no more flickering. I cant tell for sure but there may be some overscan that is going on and doesnt look like a framebuffer overflo however cant be sure:

AMD Radeon RX Vega M GL:

Chipset Model: AMD Radeon RX Vega M GL
Type: GPU
Bus: PCIe
PCIe Lane Width: x8
VRAM (Total): 4 GB
Vendor: AMD (0x1002)
Device ID: 0x67df
Revision ID: 0x00c2
Metal: Supported
Displays:
LG Ultra HD:
Resolution: 2560 x 1440 (QHD/WQHD - Wide Quad High Definition)
UI Looks like: 2560 x 1440 @ 60 Hz
Framebuffer Depth: 30-Bit Color (ARGB2101010)
Main Display: Yes
Mirror: Off
Online: Yes
Rotation: Supported
Automatically Adjust Brightness: No
Connection Type: Thunderbolt/DisplayPort
LG Ultra HD:
Resolution: 2560 x 1440 (QHD/WQHD - Wide Quad High Definition)
UI Looks like: 2560 x 1440 @ 60 Hz
Framebuffer Depth: 30-Bit Color (ARGB2101010)
Mirror: Off
Online: Yes
Rotation: Supported
Automatically Adjust Brightness: No
Connection Type: Thunderbolt/DisplayPort

[Yrp]

I found that plugging in three 4k displays shows OK, not flicker, two using miniDP, and one using a lightning port. But plugging in two 4k monitors, whether it is two miniDP, one is miniDP, one is thunder and lightning port all will flicker.

Could someone plug in three 4k monitors to test it out?

[KrisCris]

I found that plugging in three 4k displays shows OK, not flicker, two using miniDP, and one using a lightning port. But plugging in two 4k monitors, whether it is two miniDP, one is miniDP, one is thunder and lightning port all will flicker.

Could someone plug in three 4k monitors to test it out?

I can confirm that! Seems 3 display output can solve this problem... No idea why.

#172 (comment)

[Yrp]

I found that plugging in three 4k displays shows OK, not flicker, two using miniDP, and one using a lightning port. But plugging in two 4k monitors, whether it is two miniDP, one is miniDP, one is thunder and lightning port all will flicker.
Could someone plug in three 4k monitors to test it out?

I can confirm that! Seems 3 display output can solve this problem... No idea why.

#172 (comment)

One or three 4k monitors display perfectly. It may be normal to insert a few monitors.
Plug in three 4k monitors for perfect display, then unplug one of them. The remaining two monitors are also perfect.
I have no idea about this.
And why?

[fkpwolf]

same problem

[BD5HTY]

I found that plugging in three 4k displays shows OK, not flicker, two using miniDP, and one using a lightning port. But plugging in two 4k monitors, whether it is two miniDP, one is miniDP, one is thunder and lightning port all will flicker.
Could someone plug in three 4k monitors to test it out?

I can confirm that! Seems 3 display output can solve this problem... No idea why.
#172 (comment)

One or three 4k monitors display perfectly. It may be normal to insert a few monitors.
Plug in three 4k monitors for perfect display, then unplug one of them. The remaining two monitors are also perfect.
I have no idea about this.
And why?

same problem

[BD5HTY]

I bought an HDMI emulator, which perfectly solved this problem.
Double 4K will no longer flicker.
https://my.unoc.cn/downloads/hdmi.jpeg

[deftdawg]

This is a duplicate of #7 and should be closed as such... please follow that bug and try the software fix that osy86 is working on.

[osy]

Duplicate of #7