[radeon] iMac a1311 is split into four screens

[[e-mail]]

I apologize for any grammar issues, but I can barely see what I am typing. Essentially, when I installed Ubuntu, I had to do so in safe graphics mode, as the screen would otherwise split itself into four different displays that had small amounts of resolution and are rather pale. I managed to install it, but once that happend, and it restarted, it went back to being four screens. I am not sure what to do, as I cannot really read any lines of code. Thank you for your help. I am using an iMac a1311, with an HDD and installed from a flashed usb.

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: xorg 1:7.7+23ubuntu2
ProcVersionSignature: Ubuntu 6.2.0-33.33~22.04.1-generic 6.2.16
Uname: Linux 6.2.0-33-generic x86_64
ApportVersion: 2.20.11-0ubuntu82.5
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CasperMD5CheckResult: pass
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Mon Sep 25 20:33:11 2023
DistUpgraded: Fresh install
DistroCodename: jammy
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, if not too technical
GraphicsCard:
 Advanced Micro Devices, Inc. [AMD/ATI] RV730/M96-XT [Mobility Radeon HD 4670] [1002:9488] (prog-if 00 [VGA controller])
   Subsystem: Apple Inc. RV730/M96-XT [Mobility Radeon HD 4670] [106b:00b6]
InstallationDate: Installed on 2023-09-24 (1 days ago)
InstallationMedia: Ubuntu 22.04.3 LTS "Jammy Jellyfish" - Release amd64 (20230807.2)
MachineType: Apple Inc. iMac10,1
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-6.2.0-33-generic root=UUID=be40ad74-149a-443c-99b3-2dbae10973a3 ro quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 06/14/2019
dmi.bios.release: 0.1
dmi.bios.vendor: Apple Inc.
dmi.bios.version: 215.0.0.0.0
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: Mac-F2268CC8
dmi.board.vendor: Apple Inc.
dmi.chassis.asset.tag: Asset Tag#
dmi.chassis.type: 13
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-F2268CC8
dmi.modalias: dmi:bvnAppleInc.:bvr215.0.0.0.0:bd06/14/2019:br0.1:svnAppleInc.:pniMac10,1:pvr1.0:rvnAppleInc.:rnMac-F2268CC8:rvr:cvnAppleInc.:ct13:cvrMac-F2268CC8:skuSystemSKU#:
dmi.product.family: Mac
dmi.product.name: iMac10,1
dmi.product.sku: System SKU#
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.113-2~ubuntu0.22.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 23.0.4-0ubuntu1~22.04.1
version.libgl1-mesa-glx: libgl1-mesa-glx N/A
version.xserver-xorg-core: xserver-xorg-core 2:21.1.4-2ubuntu1.7~22.04.1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-2ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20210115-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.17-2build1

[Daniel van Vugt (vanvugt)]

I can't think of a good solution here, but if you would like the same "safe graphics" mode that also happens to disable the GPU, then you can edit /etc/default/grub and change:

  GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

to

  GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"

and then run:

  sudo update-grub

and reboot. Though performance will be poor.