Public bug reported: I'm a linux novice at best though I have a lot of experience with computers in general so I hope I cover all that is needed here but if not I'm sorry I will gladly provide more if needed. There are 3 issues in total that I have discovered and I don't know what this falls under but I hope this is the correct way to post this.
1. When trying to install the ubuntu or any of it variants on this machine after the GRUB screen on the boot disk the screen goes black and does nothing I had to use an older version of a live boot USB to get the OS installed, then update everything. 2. Audio issues: The master volume and the output devices seem to have issues out of the box. The audio will only work if you use either the 2.1 or 4.0 channel devices not the stereo speakers however even with this workaround the volume controls do not work. Increasing the audio level does nothing. I was able to get it working using the Pulse Audio Volume Control app thanks to a Mint Linux forum post and changing the built-in Audio profile to Pro Audio and things are now working. 3. The built in display does not dim or get brighter and there appear to be no control capabilities. This seems to be a side effect of some updates done on the kernel or so it would appear from the various forum posts I have read. It seems that the system does not know it has a backlight as there is nothing in the /sys/class/backlight folder. And no GRUB alterations seem to make any difference (it tried a number of them) This appears to be an issue across the board with all linux distros using the 6.1 kernel. I found a post from the Red Hat team stating the issue was known and that it only affected the weird or old laptops. https://hansdegoede.livejournal.com/26427.html - Forum post about this issue from RedHat. I have attached all the information I can possibly think to include as an attachment I hope this helps and if you happen to have a workaround I would love to know what it is. ProblemType: Bug DistroRelease: Ubuntu 24.04 Package: linux-image-6.14.0-27-generic 6.14.0-27.27~24.04.1 ProcVersionSignature: Ubuntu 6.14.0-27.27~24.04.1-generic 6.14.6 Uname: Linux 6.14.0-27-generic x86_64 ApportVersion: 2.28.1-0ubuntu3.8 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: donavan 1308 F.... wireplumber /dev/snd/controlC0: donavan 1308 F.... wireplumber /dev/snd/seq: donavan 1304 F.... pipewire CRDA: N/A CasperMD5CheckResult: unknown CurrentDesktop: ubuntu:GNOME Date: Mon Aug 11 14:03:06 2025 InstallationDate: Installed on 2025-08-11 (1 days ago) InstallationMedia: Ubuntu 24.04.2 LTS "Noble Numbat" - Release amd64 (20250215) MachineType: Apple Inc. iMac16,2 ProcEnviron: LANG=en_US.UTF-8 PATH=(custom, no user) SHELL=/bin/bash TERM=xterm-256color XDG_RUNTIME_DIR=<set> ProcFB: 0 i915drmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-6.14.0-27-generic root=UUID=afe5208d-2407-4b49-a716-46abc8bdcf07 ro quiet splash vt.handoff=7 PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon. RelatedPackageVersions: linux-restricted-modules-6.14.0-27-generic N/A linux-backports-modules-6.14.0-27-generic N/A linux-firmware 20240318.git3b128b60-0ubuntu2.15 SourcePackage: linux-hwe-6.14 UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 04/18/2022 dmi.bios.release: 0.1 dmi.bios.vendor: Apple Inc. dmi.bios.version: 430.140.3.0.0 dmi.board.name: Mac-FFE5EF870D7BA81A dmi.board.vendor: Apple Inc. dmi.board.version: iMac16,2 dmi.chassis.type: 13 dmi.chassis.vendor: Apple Inc. dmi.chassis.version: Mac-FFE5EF870D7BA81A dmi.modalias: dmi:bvnAppleInc.:bvr430.140.3.0.0:bd04/18/2022:br0.1:svnAppleInc.:pniMac16,2:pvr1.0:rvnAppleInc.:rnMac-FFE5EF870D7BA81A:rvriMac16,2:cvnAppleInc.:ct13:cvrMac-FFE5EF870D7BA81A:sku: dmi.product.name: iMac16,2 dmi.product.version: 1.0 dmi.sys.vendor: Apple Inc. ** Affects: ubuntu Importance: Undecided Status: New ** Tags: amd64 apport-bug noble wayland-session ** Attachment added: "output of all system information I can think to include" https://bugs.launchpad.net/bugs/2120327/+attachment/5898338/+files/late%202015%20iMac%2016%2C2%20hardware%20information.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2120327 Title: Sound and brightness issues with iMac 16,2 2.8Ghz late 2015 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/2120327/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
