Plymouth fails with kernel 6.8.0-50 to 6.11.0-17

[Russell Faull]

Plymouth fails to fully boot with this kernel when asking for encryption password for local partition. The system freezes and can be recovered in rescue mode. Previous kernels accepted the password and continued to X as expected.

Remove 'splash' from GRUB_CMDLINE_LINUX_DEFAULT="quiet" prevents plymouth from loading and booting continues to X after password is entered in when booting pauses and asks for the password in the terminal.

This behaviour is true on laptops running Linux Mint (Wilma) and Ubuntu KDE 24.04 with encrypted partitions.

On devices without encrypted partitions 'quiet splash' is included on the kernel command line and booting proceeds as expected.

Ubuntu 6.8.0-50.51-generic 6.8.12
Description: Linux Mint 22
Release: 22

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[Russell Faull (rfaull)]

Follow-up: After install the video driver nvidia-dkms-550, version 550.120-0ubuntu0.24.04.1, and inserting 'splash' in the grub kernel command on my HP Zbook (same machine as reported earlier) booting continues pausing at the graphical screen for the partition password and boots through to X as normal.

I'm wondering if the problem relates to the nouveau video driver.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Uladzimir Pasvistselik (v2p)]

From my side I can add that it was not a full system freeze, but inability to enter characters from keyboard (from both laptop one, and an external keyboard attached via USB).

Even though CapsLock LED was reacting on keypress and Ctrl+Alt+Del restarted the system.

Also I managed to do the following:
1. Waited for the very initial load of GUI with password input
2. During first 1-2 seconds I managed to type 4-5 characters - and clearly saw them represented in the input field (so in fact I saw 4-5 circles there aka "masked input")
3. Then the screen blinked once and after that I was still able to see an old input, but had no chance to enter more characters.

My system details back then were the following:
OS: Ubuntu 24.04 noble
Kernel: x86_64 Linux 6.8.0-50-generic
GPU: AMD Radeon Graphics (radeonsi, rembrandt, LLVM 17.0.6, DRM 3.57, 6.8.0-50-generic)

Now I downgraded the kernel to 6.8.0-49-generic and the problem disappeared.

[Russell Faull (rfaull)]

I agree with Uladzimir's sequence and description.

I upgraded to kernel Linux 6.8.0-51-generic, but the problem persists

[Mikael Davranche (plops)]

Same as Uladzimir Pasvistselik too: "it was not a full system freeze, but inability to enter characters from keyboard (from both laptop one, and an external keyboard attached via USB)". With 6.8.0-51.

My workaround is to boot using 6.8.0-48 or 6.8.0-51 rescue, which prevent Plymouth from being launched (and therefore, I type my password using command line).

New information:
- ctrl+alt+delete works! Which means the keyboard is kind of working... I tried lots of inputs. Only this succeeded.
- Just after the ctrl+alt+delete being pressed, and just before the system being rebooted (that's 1 second), I could see the keypad used (for me, "Ca") displayed on the screen, as usual (when the keyboard input works).

[Russell Faull (rfaull)]

A workaround on my system is to include the video driver module (in my case i915) in the initramfs.

sudo nano /etc/initramfs-tools/modules
sudo update-initramfs -u
ensure kernel command line includes 'quiet splash'
sudo update-grub
Reboot

lshw -c video will confirm that driver i915 is configured.

[Dennis Gnad (bluesceada-1)]

I can confirm that workaround with a small change for AMD integrated graphics. Instead of "i915", I added "amdgpu" to /etc/initramfs-tools/modules and do the respective commands.

Thanks @rfaull for figuring this out!

Adding additional information:
I have three Ubuntu 24.04 LTS machines with AMD graphics that use disk encryption with a password prompt during boot, but only for one of them I encountered this problem. Two of these systems were updated from 22.04, and it happened for just one of those systems.

[Mikael Davranche (plops)]

6.8.0-52 had been released. Same issue.

[Mikael Davranche (plops)]

6.11.0-17 had been released. Same issue.