I rarely post because most of the time it just works; or I find the solution on the internet. This one is, for me at least, a very weird one. Nor do I have logs but there is also nothing on the internet to guide me. I decided to post in the hope someone could help me.

Arch with LTS Kernel
Lenovo Legion 5
XFCE
Disk encryption with BTRFS/Luks.

Issue:
When on Battery, the root partition cannot be decrypted.

Workaround:
Plugin the laptop and the root partition CAN be decrypted.

Please, tell me I am not crazy and this is a real problem. I apologize as there is no log. I checked and could not find anything relevant. Since its a laptop, I kind of need to use as such but with this issue its not possible. It needs to remain plugged in..

Thank you for your time and help

Amendment:
After a lot of tries, the issue is not specifically with the laptop being plugged in or not. Simply, it takes a couple of tries before the password is accepted for the decryption of the root partition. That sounds already more logical The message is "no password with this passphrase"

hi
1. did you try bios upgrade already?
2. did you check if your HDD/SSD is working properly?
3. any other hardware related error ?

Thanks for r reply.
1. BIOS has been upgraded to the latest.
2. As far as I can tell SSD (Samsung EVO) is working properly. I run diag using spinrite. This is the only test I did on the SSD.
3. No other hardware errors at all. Everything else is working as smooth as one could expect.

Trying to dig a bit further, I am probably (cannot really say for sure) having the same issue as described in this blog --> https://bit.ly/3vQ0mME

The Arch forum is full of the same but with no resolve. BTW, the message is "No Key Available with this passphrase" (sorry messed it up in my first post). It started after latest LTS upgrade about 2 days ago.

I need to retype the same password over and over to have it finally accept it and let me boot into my system. Its a pain.
I also did "mkinitcpio -p linux-lts" and vconsole reports keymap=US which is correct. In any case my password is accepted after multiple tries.

hm. Probably I would revert to a previous version of cryptsetup.

Won't be trying to downgrade. I have an external encrypted disk and it works with no issue.
Finally, when testing the passphrase, it is successful.

went down the rabbit hole.
It seems (I can't say for sure) some type of resolve has come my way. I am posting for max visibility for others. The 'No Key available with this passphrase' seems to be a pretty wide spread issue and it has been for a while.
First Post --> https://bit.ly/3xTDX2h Second Post (Bug) --> https://bit.ly/3qDxMNH - Interestingly enough, I have the variable 'quiet' setup in my grub. I can't go in any more details than that because I was having a hard time to comprehend what was said. I will let the gurus take a stab at it if need be.

PS: I guess, I have somewhat got to a point where the issue is bearable. I need to enter the password only twice after the change following those posts. I am happy with the resolve. In any case, all the technical jargon is flying way above my head so I am stopping my descent into this rabbit hole