The prompt screen for password to mount LUKS on boot is black
I am using Fedora 29, I have a LUKS partition and want to mount it on boot with prompt password step. I did:
- Add mapper in file /etc/crypttab:
data /dev/sda6 none luks
- Add mount point in /etc/fstab
/dev/mapper/data /mnt/Data ext4 rw 0 0
- Disable plymouth by run command
plymouth-set-default-theme -R details
When booting I see the detail log, not splash screen as normal. But on the enter decrypt password step I only see a black screen, no prompt, nothing on the screen. I just like enter my password into a black hole then press enter. If I entered on time, the disk will be decrypted and mounted correctly, some time it not be mounted: I am not sure it because I entered wrong password or not on right moment.
How can I make my Fedora show the password prompt instead of the black screen?
Edit:
I found the problem only happen when I use 2 external monitor same time: one on VGA and other one on DisplayPort. If I only use the primary laptop's monitor or only use the VGA monitor, I can see the prompt for password. If I use 2 monitors on VGA and DisplayPort same time I only see the black screen.
Checklist: 1. when your system is booted, do you see a not used "VGA:0" (or similar) display in the displaymanager? 2. Are u using lightdm or gdm ?
if you can answere:"yes"+"lightdm" remove lightdm, install gdm => solved.
Thank rdtcustomercare, I had just found that the display is black only when I use more than 2 monitors. I am using on a laptop with 2 external monitor, one on DisplayPort and other on VGA. If I only use the primary monitor or VGA it work well, I can see the password prompt message. If I plug 2 monitors it only show the black.
I am using gdm, not lightdm so I guess the problem is gdm not working well with 2 external monitors.
We had that with lightdm on a dell laptop with a "hidden" internal vga device, so any DM has some bugs to resolve ;)