Ubuntu 20.04.1 LTS won't boot - frozen at dell splash screen

Question

dell xps 15 7590 (Core i7-9750H) (NVIDIA GeForce GTX 1650, 4 GB, GDDR5)

ubuntu 20.04.1 LTS (laptop shipped with win10 - wiped windows and installed ubuntu ~1 month ago)

bios version 1.8.1

as of 5 days ago laptop boot freezes at dell splash ("ubuntu" never appears at the bottom). only difference between this boot and last successful one was that i had a hdmi connecting laptop to a monitor this time (never connected previously, during boot or otherwise). have been trying to repair this weekend with no joy.

thru Esc -> Advanced options for Ubuntu i can boot recovery mode just fine. the os partition seems okay.

dell pre-boot diagnostics returns all-clear, but then says "no bootable device" when it tries to boot.

there are many posts here regarding boot issues. i've tried what i can to no avail. things i have tried:

• booting older kernels (5.4.0-45-generic and 5.4.0-42-generic)
• disabling secure boot (BIOS system info says "signed firmware update is enabled" so i didn't expect this to work. also there's been no bios update since ubuntu install)
• disabling all options in bios boot order (ubuntu, ubuntu firmware updates, windows boot manager), created new boot option for shimx64.efi, then rebooting
• replacing "quiet splash" with "nomodeset" in /etc/default/grub (i've read about nvidia issues)
• boot repair from usb, "recommended" option. only difference now is on boot dell logo appears, disappears for 3 seconds, reappears. pastebin results. i also ran the "boot info summary" option (after "recommended"... my mistake) and have this pastebin
• in recovery mode i checked /var/log/dmesg and syslog for obvious signs of error. they might as well be written in klingon! :-)
• in recovery mode i tried updating grub bootloader, tho i think boot repair already did this
• from usb "Try Ubuntu", i checked filesystem:

sudo fdisk -l
Device           Start       End   Sectors  Size Type
/dev/nvme0n1p1    2048   1050623   1048576  512M EFI System
/dev/nvme0n1p2 1050624 500117503 499066880  238G Linux filesystem

sudo fsck -f /dev/nvme0n1p2
fsck from util-linux 2.34
e2fsck 1.45.5 (07-Jan-2020)

Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure```
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/nvme0n1p2: 288820/15597568 files (0.8% non-contiguous), 5256908/62383360 blocks

any help would be appreciated. if there's more info required let me know. i could reinstall the os again but i want to know why this happened and how to prevent it in the future

EDIT1:

output of lspci -k | grep -EA3 'VGA|3D|Display' :

00:02.0 VGA compatible controller: Intel Corporation UHD Graphics 630 (Mobile)
        DeviceName: Onboard IGD
        Subsystem: Dell UHD Graphics 630 (Mobile)
00:04.0 Signal processing controller: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Thermal Subsystem (rev 07)
--
01:00.0 3D controller: NVIDIA Corporation TU117M [GeForce GTX 1650 Mobile / Max-Q] (rev a1)
        Subsytem: Dell TU117M [GeForce GTX 1650 Mobile / Max-Q]
        Kernel driver in use: nvidia
        Kernal modules: nvidiafb, nvidia_drm, nvidia

Answer 1

I had this exact same problem, with my Dell xps 15 7590. For me it happened when I was still using Ubuntu 20.04 but I upgraded to a more recent kernel (I think from 5.7.41 to 5.7.47 or something like that)

I was able to keep booting by always falling back to the earlier kernel version at boot time.

Then I did a release upgrade to 20.10, and of course it removed the older kernel, and only retained 5.7.47 as the fallback.

After much cursing the solution turned out to be quite simple:

Boot into recovery mode, and remove the redundant file /etc/X11/xorg.conf - which it seems contains invalid paths for the Nvidia graphics driver.

once that was done, I can boot normally using the latest kernel, in 20.10

See https://forums.developer.nvidia.com/t/ubuntu-18-lts-nvidia-440-unable-to-make-nvidia-the-primary-display-driver/107632/4 for more about this

Also see https://itsfoss.com/fix-ubuntu-freezing/ and specifically the comment from Klavs (which is how I discovered this fix).