Cannot choose resolution 5120x1440
 

Hi,

I am running Ubuntu 21.04 on wayland and have a Philips 498P9 5k ultrawide connected to a Dell D6000 which is connected through USB-C to a Dell Latitude 5300.

The screen is connected via Displayport cable to the dock.

As to my understanding I should be able to choose the full native resolution at 60Hz.

The maximum resolution I can choose is 3840 x 1080 at 59,97 Hz both using Xorg and Wayland.

I am using the latest driver (5.4) and as per release notes it should be possible:

Any help is appreciated

Thank you

Update: I was able to get the screen working with native resolution when connected directly to HDMI to the laptop, unfortunately that only does 30Hz. I needed to add the resolution manually and this only worked in X, not Wayland. So currently using X instead of Wayland again at 30Hz which is far from optimal... Adding the same resolution (30Hz or 60Hz) when the display is connected to the D6000 dock does not work though, when the resolution switches the display just turns black.

Update 2: I have another, small portable Dell DA300 dock. With that dock connected to USB-C and the display connected via Displayport to this dock I was able to use 5120x1440@60Hz out of the box:

D6000 gives the following xrandr output when the display is connected via Displayport:

I was able to test this with a Windows 10 machine and the latest available drivers (10.1 M1) and I was able to run native resolution 5120x1440, even at 70Hz.

Attachment 4123

D6000 was connected via USB-C and screen via Displaylink. That means, the dock can actually handle it and it seems that this is something that needs to be fixed in the Linux driver.

Is there any chance that technical support can look at this? I tried to email but it bounced back. I would be more than happy to test a possible fix.

Thank you