Bug 234625 - iMac early 2008 garbled screen during install from USB stick
Summary: iMac early 2008 garbled screen during install from USB stick
Status: New
Alias: None
Product: Base System
Classification: Unclassified
Component: kern (show other bugs)
Version: 12.0-RELEASE
Hardware: amd64 Any
: --- Affects Only Me
Assignee: freebsd-bugs mailing list
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2019-01-05 00:14 UTC by Jason W. Bacon
Modified: 2019-01-07 20:27 UTC (History)
0 users

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Description Jason W. Bacon freebsd_committer 2019-01-05 00:14:34 UTC
After loading text, data and syms, the screen switches modes and becomes unreadable.  After booting completes you can make out a blue background and whitish stripe across the middle of the screen which would be the first menu.

By booting into OS X I determined that the iMac has a Radeon GPU.

I was able to get around the problem as follows:

1. After booting to the first menu, type Ctrl+Alt+F4 to get to a shell.  The screen is still garbled here, so this alone does not help.

2. Blindly type "kldload radeonkms".  The screen then resets to a readable state.

I have not tried 11.2 on this machine, but would be willing to if it might help isolate the issue.
Comment 1 Jason W. Bacon freebsd_committer 2019-01-05 00:37:57 UTC
Followup:

Must use the same trick when booting from installed system.

To fix add the following to /etc/rc.conf:

kld_list="radeonkms"
Comment 2 Jason W. Bacon freebsd_committer 2019-01-07 20:27:15 UTC
11.2-RELEASE exhibits the same issue.