Bug 207613 - Won't boot
Summary: Won't boot
Status: NEW
Alias: None
Product: Drivers
Classification: Unclassified
Component: Video(DRI - non Intel) (show other bugs)
Hardware: x86-64 Linux
: P1 high
Assignee: drivers_video-dri
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-05-07 13:47 UTC by Michael Fox
Modified: 2020-05-07 16:25 UTC (History)
1 user (show)

See Also:
Kernel Version: 5.7.0.994
Subsystem:
Regression: No
Bisected commit-id:


Attachments
dmesg from 5.7.0.994 boot attempt (105.43 KB, text/plain)
2020-05-07 13:47 UTC, Michael Fox
Details

Description Michael Fox 2020-05-07 13:47:11 UTC
Created attachment 288979 [details]
dmesg from 5.7.0.994 boot attempt

Applies to a 2015 5k iMac 27" with AMD r9390x video card. I was asked to file this as I have been testing 5.3, 5.4, 5.6 and 5.7 kernel, all of which boot very slowly (> 3 minutes to working desktop), and also have delayed wakeup from display sleep (~2 minutes) and delayed shutdown (~ 2 minutes). dmesg and systemd analysis for these boots have been posted in bugs.launchpad.net/bugs/1875211.

I have been asked to test several of the 5.7 rc kernels and the latest version (5.7.0.994). Only one of these versions would boot at all (rc3); the other rc kernels would only get as far as the login screen, and 5.7.0.994 wouldn't get even that far. Attached is the dmesg to the 5.7.0.994 boot attempt.
Comment 1 Alex Deucher 2020-05-07 15:31:23 UTC
Did this system ever work?  If so when and can you bisect?
Comment 2 Michael Fox 2020-05-07 16:25:54 UTC
(In reply to Alex Deucher from comment #1)
> Did this system ever work?  If so when and can you bisect?

Yes, it works well with the 4.15 kernel. And I did bisect to the extent of finding out the point at which the slow boot occurred. You can follow it here:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1874104

In a nutshell, kernels 5.0, 5.1 and 5.2 are fine. The last good (i.e. normal booting) kernel was 5.2.21. Kernel 5.3.rc1 was the first slow booting version. Kernels I tried that are slow booting are 5.3.0, 5.3.1, 5.6, and the 5.6 rc's leading up to 5.7.0.994. I don't think I am technically competent enough to dissect within a kernel.

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