Arch Linux

hylianloach

Member

Registered: 2019-05-25

Posts: 4

initramfs encrypt module silent password prompt

Hello all.

I've got Arch set up with LVM on LUKS2.

It's working perfectly, but one thing has been bugging me. After the kernel loads and it hits up the initramfs, I do not get a password prompt.

Don't get me wrong, I am able to enter my password and boot into the system, but there is absolutely no feedback if I've typed my password, or if input is being accepted. In other words, the console is *accepting input*, but it is completely silent. It doesn't even ask me for my password - I sorta have to just wait for a second or so before I start typing. I get a couple of lines of text about loading the initramfs, so my console output is clearly working.

I've extracted the initramfs to explore what exactly is being done and there doesn't appear to be anything in the encrypt hook that actually prompts for the password? I haven't dug deep enough though so I'm not sure if there's something else that's supposed to be doing this.

Here is some config I've got going:

HOOKS=(base udev autodetect keyboard modconf block encrypt lvm2 filesystems fsck)

If anyone has any idea what's going on, that would be really super helpful! Thank you.

Note I've turned off splash and quiet:

GRUB_CMDLINE_LINUX_DEFAULT="cryptdevice=UUID=5fc056b6-df26-47b0-9686-b0c15b7a452c:cryptlvm:allow-discards root=/dev/VG_1/root"
GRUB_CMDLINE_LINUX=""

Quiet and nosplash are definitely not being passed. Not sure if it's relevant at all.

menuentry 'Arch Linux' --class arch --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-2bba397b-7543-466f-8a13-08262678ce15' {
	load_video
	set gfxpayload=keep
	insmod gzio
	insmod part_gpt
	insmod ext2
	if [ x$feature_platform_search_hint = xy ]; then
	  search --no-floppy --fs-uuid --set=root  65989ceb-d04a-48b5-a578-f41ab4ba2146
	else
	  search --no-floppy --fs-uuid --set=root 65989ceb-d04a-48b5-a578-f41ab4ba2146
	fi
	echo	'Loading Linux linux ...'
	linux	/vmlinuz-linux root=/dev/mapper/VG_1-root rw  cryptdevice=UUID=5fc056b6-df26-47b0-9686-b0c15b7a452c:cryptlvm:allow-discards root=/dev/VG_1/root
	echo	'Loading initial ramdisk ...'
	initrd	/initramfs-linux.img
        # This is where I should be getting prompted by initramfs-linux for my password, but I don't :(
}

Last edited by hylianloach (2019-05-25 13:04:34)

frostschutz

Member

Registered: 2013-11-15

Posts: 1,418

Re: initramfs encrypt module silent password prompt

So... any other messages besides Loading Linux ... loading ramdisk ...?

Those messages are printed by grub. You want messages printed by the kernel.

If you get no messages at all there might be something odd going on with the console in general.

Otherwise if kernel is printing messages fine and just the password prompt itself is missing, something odd with the initramfs.

Sometimes just re-building the initcpio ( from the actual properly booted system, not live cd chroot ) does the trick. You can also try the fallback initramfs or remove autodetect from your mkinitcpio.conf.

hylianloach

Member

Registered: 2019-05-25

Posts: 4

Re: initramfs encrypt module silent password prompt

I see:

Loading Linux linux ...
Loading initial ramdisk ...
_

That's it. Then I just type in my password blindly and hope that everything is working. I get no messages at all until the initramfs hands things over to systemd. I'll try the fallback image.

EDIT: Tried the fallback image. Didn't work - still not seeing any messages.

I rebuilt the initramfs but it still didn't help.

EDIT: Tried setting GRUB_TERMINAL_OUTPUT=console to disable the graphical terminal but it didn't help either. Definitely lost to why I'm getting no output at all.

Last edited by hylianloach (2019-05-25 15:09:37)

frostschutz

Member

Registered: 2013-11-15

Posts: 1,418

Re: initramfs encrypt module silent password prompt

console not working at all then

can you tell us more about the hardware?

hylianloach

Member

Registered: 2019-05-25

Posts: 4

Re: initramfs encrypt module silent password prompt

Sure - I'm using the HP Spectre x360 (https://wiki.archlinux.org/index.php/HP … 13-ap0xxxx)

I did not need to follow any of the workarounds for installation - UEFI and Secure Boot are both enabled (using shim to secure boot), and I'm dual booting windows perfectly fine with Bitlocker still enabled.

Last edited by hylianloach (2019-05-26 04:10:13)

hylianloach

Member

Registered: 2019-05-25

Posts: 4

Re: initramfs encrypt module silent password prompt

So, I did a bit more experimentation and I found that setting early  KMS start (https://wiki.archlinux.org/index.php/Ke … _KMS_start) fixes the problem - I need to add i1915 into the modules for my initramfs.

This works - I see the password prompt now. However it's definitely a bit slow - I don't get any text until a few seconds later.

It seems weird that I'd need to do this to get console messages to show up in the first place. Does anyone have any idea of a solution that doesn't involve hacking in an early KMS

Last edited by hylianloach (2019-05-26 09:02:54)