External display does not allow higher refresh rate

Hey there,

so this thing has been happening to me for the past two weeks. I have two external displays (one larger, one smaller) connected through a dock to my laptop running Arch. When I connect only one of the displays, the connected display is at its full supported refresh rate (60 Hz). When I connect both of the displays (and set the refresh rate to maximum), the larger (4k) one shows a black screen and displays “No data received”, even though it is visible in Gnome settings.

My setup was fully functional just until two weeks ago and I am kinda desperate right now… Tried reconnecting everything, replaced cables etc.

Here are some details about my setup that I find relevant to this problem:

Laptop: Framework 13, AMD Ryzen 7 7840U with Radeon 780M graphics; Running Arch Linux with Gnome on Wayland
Larger display: Samsung 32", 3840x2160 at 60Hz
Smaller display: Dell, 2560x1440 at 60Hz

The dock is not the problem and neither are the cables.

Report from xrandr --props. The first one is my built-in display, second is the smaller display, third is the larger one.

Screen 0: minimum 16 x 16, current 5280 x 4064, maximum 32767 x 32767
eDP-1 connected primary 2256x1504+786+2560 (normal left inverted right x axis y axis) 280mm x 190mm
        RANDR Emulation: 1
        non-desktop: 0
                supported: 0, 1
   2256x1504     59.93*+
   1920x1440     59.90
   1600x1200     59.87
   1440x1080     59.99
   1400x1050     59.98
   1280x1024     59.89
   1280x960      59.94
   1152x864      59.96
   1024x768      59.92
   800x600       59.86
   640x480       59.38
   320x240       59.52
   1920x1200     59.88
   1680x1050     59.95
   1440x900      59.89
   1280x800      59.81
   1152x720      59.75
   960x600       59.63
   928x580       59.88
   800x500       59.50
   768x480       59.90
   720x480       59.71
   640x400       59.95
   320x200       58.96
   2048x1152     59.90
   1920x1080     59.96
   1600x900      59.95
   1368x768      59.88
   1280x720      59.86
   1024x576      59.90
   864x486       59.92
   720x400       59.55
   640x350       59.77
DP-14 connected 1440x2560+3840+0 right (normal left inverted right x axis y axis) 600mm x 340mm
        RANDR Emulation: 1
        non-desktop: 0
                supported: 0, 1
   2560x1440     59.91*+
   1920x1440     59.90
   1600x1200     59.87
   1440x1080     59.87
   1400x1050     59.86
   1280x1024     59.76
   1280x960      59.94
   1152x864      59.78
   1024x768      59.68
   800x600       59.86
   640x480       59.38
   320x240       59.52
   1920x1200     59.88
   1680x1050     59.85
   1440x900      59.89
   1280x800      59.81
   1152x720      59.75
   960x600       59.63
   928x580       59.88
   800x500       59.50
   768x480       59.38
   720x480       59.71
   640x400       59.20
   320x200       58.96
   2048x1152     59.90
   1920x1080     59.88
   1600x900      59.82
   1368x768      59.88
   1280x720      59.86
   1024x576      59.90
   864x486       59.45
   720x400       59.55
   640x350       59.77
DP-12 connected 3840x2160+0+400 (normal left inverted right x axis y axis) 700mm x 400mm
        RANDR Emulation: 1
        non-desktop: 0
                supported: 0, 1
   3840x2160     29.98*+
   2048x1536     29.95
   1920x1440     29.95
   1600x1200     29.95
   1440x1080     29.86
   1400x1050     29.98
   1280x1024     29.90
   1280x960      29.82
   1152x864      29.92
   1024x768      29.89
   800x600       29.55
   640x480       29.85
   320x240       27.50
   2560x1600     29.99
   1920x1200     29.95
   1680x1050     29.95
   1440x900      29.91
   1280x800      29.83
   1152x720      29.96
   960x600       29.86
   928x580       29.64
   800x500       29.53
   768x480       29.64
   720x480       29.25
   640x400       29.58
   320x200       26.53
   3200x1800     29.96
   2880x1620     29.96
   2560x1440     29.94
   2048x1152     29.94
   1920x1080     29.95
   1600x900      29.92
   1368x768      29.94
   1280x720      29.93
   1024x576      29.84
   864x486       29.50
   720x400       29.51
   640x350       29.03

I’d be very happy for a solution but also just for direction to where to report a bug (or where to find a solution). Should I just wait until an update of something fixes this?

Cheers,

Martin

Looks like there is an MST hub in the dock. And both displays share bandwidth along the DP connection to said MST hub and somehow, the bandwidth is limited now and that is why resolutions that would not fit into the remaining bandwidth are removed as options.

Probably… but the thing is that this started happening two weeks ago. I tried buying the same dock again (a new piece) but I see the same behavior. Do you think this is a software issue (driver, etc)?

I’d look at what software has changed in the last two weeks. Unfortunately with Arch, it might be a lot.

You might try booting with a Ubuntu live USB and see if the issue exists there.

2 Likes

Looks like it is a kernel regression.

It is (hopefully) going to be fixed in 6.10.5

If someone is experiencing the same problem, just use LTS kernel for a while.