2 external monitors via dock doesn't work

hey everybody, I just got my new type c dock( 2 hdmi 1vga) but i am having some problems with it, I want to connect 2 external displays to the dock .
I have 3 displays:
my laptop display(eDP-1) 1920x1080
my wide monitor (DP-2-9) 2560x1080 connected via the hdmi port on the dock
second monitor (DP-2-8) 1920x1080 connected via the vga port on the dock.

when connecting both of the displays (VGA and hdmi) the wide monitor doesnt work, it shows on the settings that it is connected but it doesnt have any output.
I tried to use xrandr to configure the monitors and enable them one by one but when I try to enable the wide monitor it output

configure crtc 2 failed

I tried this solution but with no luck,then I tried to set the resolution of the wide monitor to 1920x1080 and it works but it is not the full resolution.
does anyone know if it can be fixed?
output of xrandr --verbose
Update: it seems to have the same problem on windows on different configurations and setups , it just don’t recognize the displays configuration and doesn’t allow to set resulotion higher then 1920x1080.

Looks like that the VGA port limit is 1920x1080 alias your monitor (I guess an older one ?!) limits de resolution.

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That sounds like it is an issue with the dock hardware itself not supporting higher resolutions.
There have been threads here about issues with the dock and monitors attached when the system sleeps or suspends as well.

The thing is , it “supposed” to support up to 4k 30 fps on each HDMI port, also it does work when only the HDMI wide screen is connected and I tried to lower the fps as many post with similar problems suggested.

You said the wide screen is supposed to support its full resolution at 60 Hz refresh, and the doc is supposed to support up to 4k at 30 Hz refresh. This implies that with the 60 Hz refresh the doc will not support the higher resolution.

In the gnome control panel settings → display it allows selecting the display screen but does not indicate the refresh rate when multiple displays are attached for me.

xrandr however should show each display and the current refresh settings. xrandr is also a tool that can be used to change specific settings related to each monitor.

I cannot test since I do not have a dock, but am only using the built-in at 144 Hz and one external hdmi at 60 Hz (both are only capable of 1920x1080)

Maybe someone else can jump in here with experience similar to your setup and assist.


Speaking generically, most machines I’ve had recently have a setting in the BIOS for DisplayPort over Dock/USB-C that basically let’s you choose between one monitor at higher resolution or multiple at lower resolutions/framerates. IE, most I’ve had in recent years support one monitor at 4kp30 or multiple at 1080p60. Additionally, some monitors only support full resolution with a certain interface (HDMI or DisplayPort). Further complicating things is whether your Dock and USB-C are actually Thunderbolt and if they were, what version of DisplayPort they support. If the monitor only supports it fully over HDMI, keep in mind that the HDMI port on your thunderbolt Dock is likely emulated via DisplayPort. If all this sounds terrible, it’s because it is. There are a ton of hardware variables before Fedora even gets a chance to play.


The thing is that the dock works fine with one screen attached to it, the problem happens when I connect another screen.
I tried to use xrander to fix the problem but I still keep getting the error
“configure crtc 2 failed”
When running
“xrandr --output DP-2-9 --mode 2560x1080”
This command works fine with one screen attached but not with two
Also I double checked that DP-2-9 is the currect screen

Thank you ,very informative.
The bios settings is worth to take a look at , it might be the problem although i used 2 different laptops to test
One run Linux +thunderbolt for sure
And the second is windows 10 with type c

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