Hi Ian, I have tested the mainline kernels, and the problem seems to be upstream, indeed.
The last working version is 6.6.109. With this version the secondary display syncs correctly and all video modes are available. 6.6.110 fails. Currently I'm running 6.18.1 (6.18.1-061801-generic #202512121839 SMP PREEMPT_DYNAMIC Fri Dec 12 19:19:06 UTC 2025), and with this I have a partial solution (laptop's HDMI works on boot, but losses whenever the screen gets locked and then I need to re-plug it). Just for curiosity I tested the latest amd64 version available (6.18.1), and it almost works. The external hub HDMI works during boot (it doen't work with 6.6.109), but loses sync when the desktop starts. Re-plugging the display fixes it. Just ask if I can help with anything else. El 7/1/26 a les 0:48, Ian Whitfield ha escrit: > Hi, thanks for reporting a kernel regression! > > Do you know the version of the LTS kernel which was last working? If you > reinstall that older kernel and boot into it, does the issue go away? > This would help us narrow down what patches to look at. > > Trying an upstream stable kernel would also tell us if the regression is > on Ubuntu's side or upstream. Could you try to reproduce the problem > with this mainline kernel:https://kernel.ubuntu.com/mainline/v6.6.119/ > ? A guide to installing mainline kernel packages is available at > https://wiki.ubuntu.com/Kernel/MainlineBuilds > > ** Changed in: linux (Ubuntu Noble) > Assignee: (unassigned) => Ian Whitfield (ijwhitfield) > -- <https://www.robsurgical.com> Daniel Guerrero Miralles Software Team Lead [email protected] Aquest missatge pot contenir informació confidencial i/o privilegiada. Si no sou el destinatari, si us plau informeu al remitent i elimineu el missatge. Este mensaje puede contener información confidencial y/o privilegiada. Si no es el destinatario, por favor informe al remitente y elimine el mensaje. This message may contain confidential and/or privileged information. If you are not the addressee, please notify the sender and delete the message. ** Attachment added: "wgRyuS9lbvv8tst8.png" https://bugs.launchpad.net/bugs/2136103/+attachment/5939235/+files/wgRyuS9lbvv8tst8.png -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2136103 Title: [i915] Limited resolutions in monitors connected via USB hub when using 6.8.0-90.91-generic To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2136103/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
