[Bug 1877889] Re: Intermittent hangs on boot Ubuntu 20.04 on Lenovo E595

So, what are the next steps here (if any)?

To summarize, the regular Ubuntu 20.04 GA kernel (v5.4) works reliably
for me so long as "nomodeset" is provided as a kernel boot parameter.
Without this parameter that kernel and others I was invited to test all
hang occasionally on boot.

Is there anything more that needs to happen on this ticket? Do you need
me to test other kernel builds for example?

Or, is the issue "resolved", and I should keep using "nomodeset"
indefinitely?

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https://bugs.launchpad.net/bugs/1877889

Title:
Intermittent hangs on boot Ubuntu 20.04 on Lenovo E595

Status in linux package in Ubuntu:
Confirmed

Bug description:
Hello,
I see occasional hangs on boot. The hangs occur after entering the LUKS decryption password for the root filesystem, and before the login screen is displayed. The "/boot" filesystem is not encrypted, so the initramfs is loading fine etc. The hangs are intermittent. Sometimes I don't see a hang for 10+ boots in a row, and sometimes I'll get a hang 5 times in a row.

When the hang occurs the boot splash screen is visible (not the login
screen). The system is still responsive to SysRq keys, so I can
somewhat safely issue S+U+S+B sequence to try booting again without
corrupting much.

I have tried removing the "quiet splash" kernel parameters that are
enabled by default on Ubuntu desktop to see if any interesting
messages occur that way. So far however I have not experienced a hang
with "quiet splash" removed.

This system is a Lenovo E595 (Ryzen 3500U) with the latest BIOS from
Lenovo installed (v1.16), running Ubuntu 20.04 desktop. I am
submitting this bug using `ubuntu-bug linux-image-generic`, but I
don't know for sure if this is a kernel issue or something else.

I suspect my bug might be the same as this one already reported (
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1873594 ), but
I'm filing my own anyway as a means to capture more details of my
system.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: linux-image-generic 5.4.0.29.34
ProcVersionSignature: Ubuntu 5.4.0-29.33-generic 5.4.30
Uname: Linux 5.4.0-29-generic x86_64
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC1: paul 2507 F.... pulseaudio
/dev/snd/controlC0: paul 2507 F.... pulseaudio
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Sun May 10 20:09:53 2020
MachineType: LENOVO 20NFCTO1WW
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.4.0-29-generic root=UUID=f466d4ea-c251-4721-b071-bd70c82f00e1 ro rootflags=subvol=@ splash quiet vt.handoff=7
RelatedPackageVersions:
linux-restricted-modules-5.4.0-29-generic N/A
linux-backports-modules-5.4.0-29-generic N/A
linux-firmware 1.187
SourcePackage: linux
UpgradeStatus: Upgraded to focal on 2020-04-24 (15 days ago)
dmi.bios.date: 03/30/2020
dmi.bios.vendor: LENOVO
dmi.bios.version: R11ET36W (1.16 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20NFCTO1WW
dmi.board.vendor: LENOVO
dmi.board.version: Not Defined
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrR11ET36W(1.16):bd03/30/2020:svnLENOVO:pn20NFCTO1WW:pvrThinkPadE595:rvnLENOVO:rn20NFCTO1WW:rvrNotDefined:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad E595
dmi.product.name: 20NFCTO1WW
dmi.product.sku: LENOVO_MT_20NF_BU_Think_FM_ThinkPad E595
dmi.product.version: ThinkPad E595
dmi.sys.vendor: LENOVO

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