@Edent what’s the hub? I’m wondering if it is actually DisplayPort or if it is using DisplayLink to get a display over USB (rather than using DisplayPort connections to your laptop over the usb-c cable) if it’s displaylink it’s a driver thing and nothing to do with your GPU.
@Edent ah wait, that’s a DP1.2 GPU not 1.4 so it won’t do USB3 And 4k60 over one cable, you’d need to make it use the usb2 lines so all the lanes are for DP (if it’s DP proper and not displaylink). Not sure how you force Linux to do that, bar maybe unloading the usb3 kernel modules.
@Edent ah well that CPU doesn’t support 4k60 on hdmi so that’s no mystery at least. It’s still hard to get full hdmi 2.1 on laptops annoyingly, with 4k120/10bit HDR for modern screens. Note the gotcha here that much of 2.1 spec is optional so you need to check details :-(
@Edent: xrandr in a command-line will hopefully show you useful things. (This can also be used to issue commands.)
Had this recently on my own device, it struggled to display both locally and on the 4K display. I found that increasing the amount of RAM allocated to the on-board graphics (in the BIOS) helped; I suspect the graphics hardware was always capable of it, but constrained by the default configuration.
@Edent With the external display running, you could try disabling the on-board; if the capabilities improve, it indicates some kind of resource bottleneck in your device rather than a connectivity problem outside it.
@Edent I think it should just be xrandr if you're on X and not Wayland. That should show you all the available resolution/refresh rate configurations supported natively by your card and drivers. Having a hub could definitely make it harder to find the problem though :/
@kevinctofel interesting, thanks.
I'm using Wayland (otherwise external screens tear horribly).
I'll try booting into an X session to see if that works.
@Edent Good question as both xrandr for X and wlr-randr for Wayland only show monitors resolutions I think ? Maybe I'm wrong though and it could be the GPU's min and max resolutions ??
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