Score:0

Ubuntu sets refresh rate to 120 Hz automatically

nu flag

I recently bought two new Dell P2723DE displays (27 inch, 2560x1440). I have them set up in a daisy chain configuration, connected to my stationary dual boot (Windows 10 and Ubuntu 20.04) computer. The setup works well on Windows 10 with no additional configuration than simply plugging the monitors in. However, when I boot into Ubuntu the displays say "No DP connection".

I tried plugging in my old Dell P2419H, which works. Having them all plugged in at the same time and going into display settings shows that Ubuntu automatically sets the refresh rate to 120Hz on the 27 inch monitors, which they do not support. I tried to set it to 60 Hz, but they still won't display anything.

schematic picture of my setup

Does anyone have any idea what the problem might be?

Score:0
gb flag

I don't have the same problem, but I got the same monitor, with ubuntu 2204 and lenovo laptop with ryzen and after connecting the usb-c cable everything works good but just for few seconds and it disconnects, after few seconds reconnects and it happens randomly or after click or enter or etc (keyboard and mouse in usb hub in monitor).

So, I'll let you know but I think its that there are missing some driver, which could be in ubuntu 2210. Try booting to live system and it could work. I have this problem today and don't have usb with me, so I'll try it in next days.

There could be workaround to your problem with toying with xrandr, its pain when you have so many monitors but you can try. For example:

xrandr
xrandr --output HDMI-1 --mode 1920x1080 --rate 60

I switched to X11 from wayland to try it, but it didn't help. Maybe it will help you (while logging in choose on settings button

For wayland you could use different tools

  • gnome-randr (gnome)
  • kscreen-doctor (kde)

TLDR: monitor is new (august 2022) and in linux it needs some missing drivers which could be in new up to date distro like fedora

I sit in a Tesla and translated this thread with Ai:

mangohost

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.