After updating Lubuntu 22.04.1 lts to 24.04.1 lts, the cryptsetup prompt to enter the password to decrypt the root partition no longer appears on an external monitor attached to the laptop where Lubuntu is installed. Rather, it only appears on the built-in display. In Lubuntu 22.04, the prompt always appeared on both displays, whether the laptop lid was open or not. Now on 24.04 it does not show up at all on the external monitor regardless of the state of the lid. Once the correct password is entered, the external display works as desired and configured, showing the user login prompt. I can’t figure out how to tell cryptsetup that there are multiple displays and to please use them both to ask me to decrypt root. I never encountered this issue in Lubuntu 22.04
I can’t help, and my understanding is far too limited to be exact sorry… however
Your system isn’t fully functional as its still early in the boot process when you enter the encryption key, thus your hardware and its firmware have an influence on how it operates. I’ve used laptops where I could control which display showed (ie. internal and/or external) grub & the decryption prompt via firmware (BIOS) settings and/or fn-keys on the device, and other laptops where I had no control. I’ve also noted using the exact same software, different devices operating differently at this early stage (due to their different hardware & firmware with identical software configurations).
Ubuntu 24.04 (and I consider Lubuntu a Ubuntu system, thus my wording) is two years newer in regards software (kernel stack can differ as I don’t know if you were using GA or HWE kernels, with Lubuntu this default is set by what install media you use) thus the software stack component has changed, which influences how your machine operates… but I’m not sure how much control you have, and do believe what control you do have will very much be specific to your hardware given the OS isn’t fully operational yet.
I can’t help sorry, but I am warning I suspect you’ll find your answer may not perfectly match what works for others using different hardware, as I suspect your issue is hardware/firmware specific.
Thank you,guiverc, for the observations.
Regarding “…if you were using GA or HWE kernels, with Lubuntu this default is set by what install media you use”, I was running the 24.04 upgrade from the 22.04 installation Software Updater, so there was no external media being used. This was the 22.04 install that displayed cryptsetup prompts on both monitors. Does this clarify the GA or HWE kernel issue?
Regarding “Your system isn’t fully functional as its still early in the boot process when you enter the encryption key”, the 22.04 cryptsetup is running in a known 2-monitor environment so is the process or configuration file that establishes that 2-monitor environment now skipped or mis-configured when 24.04 runs cryptsetup? Could that be corrected by resequencing or reconfiguring an underlaying boot process?
Regarding “… I consider Lubuntu a Ubuntu system”, is it appropriate to ask about this behavior in Ubuntu discourse? I would expect to possibly get some pushback about “boundaries”.
Lubuntu 22.04 & 22.04.1 LTS media installs using the GA kernel stack, where as Lubuntu 22.04.2 thru 22.04.5 media will install with the HWE kernel stack. When you release-upgrade to later releases (ie. 24.04), your default stack remains the same; being set by your install media.
If you installed your system with a stack (say HWE) at 22.04, and then added the other stack (so your system has installed & offers at grub both GA & HWE choices), when you release-upgrade to 24.04 you’ll remain with both kernel stack options. The GA kernel for 24.04 is 6.8, where the next HWE kernel is 6.11; only available now if you’re using edge-proposed, or
linux-image-generic-hwe-24.04-edge | 6.11.0-12.13~24.04.1 | noble-proposed | amd64, arm64, armhf, ppc64el, s390x
but that kernel will advance until it’s available for normal users; ie. 24.04 is still somewhat new & hasn’t yet got its first HWE kernel being 6.11 from 24.10; but it’s visible & coming.
Ubuntu Forums is now using the Ubuntu Community Hub or Ubuntu’s discourse, and Ubuntu Forums allows questions about any official Ubuntu flavor including Lubuntu. I wouldn’t expect pushback if you asked questions there (I’m a mod there too if you look; and not the only person here who can say that either). We do appreciate it when people don’t ask a question at multiple support sites at the same time! but try one site, and only move/try seeking help at other sites if they didn’t get help at their first site (we have no issues with that approach).
Sorry I can’t provide help (or even opinion) on that question.
Thank you for the additional information.
My understanding is that I’m performing 24.04 release-upgrade which uses the default kernel stack which in my case should be HWE since it came from release-upgrade of 20.04. And the HWE kernel stack for Linux kernel 6.1 in 24.04 is still to come for normal users. Am I getting it??
I tried looking at System Profiler in 22.04 but don’t see anything regarding GS or HWE stack. Is there a command line to try or somewhere else to look?
If I hold back on 24.04 upgrade waiting for HWE stack to be available to normal users, is there a way to know when to try again to run release-upgrade?
TLDR;Sorry about the convoluted approach I’m attempting, but I’ve had a dual-boot, Linux root encrypted setup since Lubuntu 18 and none of the media releases of Ubuntu or Lubuntu since then have facilitated that setup. Until now (24.04), the release-upgrades since 18.04 have worked cleanly until this minor glitch appeared in 24.04. I can live with the cryptsetup prompt on the laptop display if I can’t get by it, its just inconvenient.
Lubuntu 20.04 was provided on ISOs using the GA (two) and HWE (four) kernel stack, so your release-upgraded system will use whatever you set your systems default to by your use of install media. Both GA & HWE on 24.04 are currently 6.8, however whether or not your system remains on 6.8 will depend on initial install media.
typo I assume; ie. you meant 6.11, and my CLI enquiry gets the same result as it did in my last answer; I see it only in edge proposed.
You’ll get 6.11 if using the HWE kernel and your system wasn’t made with 20.04 media that only used/installed the linux-image-generic kernel (ie. GA kernel stack); as Ubuntu flavors (Lubuntu) provide media that installs both GA & HWE.
Your default is set by your install media; holding back on the release-upgrade does nothing, except change what kernel you initially upgrade to; as HWE and GA are both currently 6.8, but systems with the the HWE kernel will upgrade to 6.11 (from 24.10) but systems using GA will remain on 6.8. If you release-upgrade 14 months from now and your existing system is using GA you’ll still get 6.8 on your release-upgrade, but if using the HWE kernel you’ll get what is currently expected to be 6.14. Your default set by your install media (unless you changed it via package commands).
You should be able to view your install media with the command
cat /var/log/installer/media-info
I’ve now determined its apparently not an update issue, it is seemingly inherent in 24.04 itself. I finally figured out how to get the 24.04 iso installer to give me a dual-boot encrypted-root system and it looks just like the release-upgrade , no cryptsetup prompt on the external monitor. Disappointing in a way, that it seems to be a feature, rather than a bug as I found it quite useful and am sorry its been “deprecated” 
Thanks for the respect 
This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.