Behind the Eyes

Tag: Mac

  • Updating iMac 2015 5K model to use AMDGPU kernel drivers in Ubuntu 26.04

    Hello. I acquired a 2015 iMac with 5K display. Unfortunatly this Mac doesn’t support the latest version of MacOS, so I decided that I would install Ubuntu on it. The installation was straight forward. I have a blog on this site that details how to install Linux on Apple systems. Just following that Blog to install Ubuntu on an iMac.

    So I have been running it pretty consistantly and haven’t had any issues until I noticed that if I try to stream video through Brave or Chrome broswers, or really any web browser, the performance was terrible. I did find that I could disable hardware accelleration in Brave and Chrome, but some sites it worked, most it did not.

    After some online searching I found out that Ubuntu 26.04 by default on older AMD Graphics cards, which this system does have, it uses the older radeon kernel driver. So, as a test, I decided to try to force the newer amdgpu driver and use that instead.

    To do this I had to black list the radeon driver and enable the amdgpu driver, and then I found a couple of other parameters to get this working smoothly.

    First, you need to update the /etc/default/grub configuration. I like to use vi so:

    sudo vi /etc/default/grub

    Once I have the file open, look for the line:

    GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

    We’re going to modify this line to blacklist the radeon driver and use the amdgpu driver. After splash, we need to enter the following:

    radeon.cik_support=0 amdgpu.cik_support=1 amdgpu.dc=1 amdgpu.ppfeaturemask=0xfff7bffd

    The full GRUB_CMDLINE_LINUX_DEFAULT should look like this:

    GRUB_CMDLINE_LINUX_DEFAULT="quiet splash radeon.cik_support=0 amdgpu.cik_support=1 amdgpu.dc=1 amdgpu.ppfeaturemask=0xfff7bffd"

    Save the configuration by pressing the ESC key and typing :wq to save and quit vi.

    Next, reboot your computer. Once it starts up, you can run the following command to verify that you are using the amdgpu driver:

    lspci -k | grep -E -A 3 "VGA|3D"

    This will be the output:

    01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Amethyst [Radeon R9 M395/ M395X Mac Edition] (rev 01)
        Subsystem: Apple Inc. Device 014c
        Kernel driver in use: amdgpu
        Kernel modules: amdgpu

    Now, if you disabled graphic accelleration in your web browser, you can re-enable it and try going to a site like YouTube and stream a video and you will notice it is working correctly and streaming normally.

    I hope this helps.

  • Installing Ubuntu 20.04.2 on Macbook Pro Mid 2012

    Hello everyone. Been a while and I have a new blog entry so that I don’t forget how to do this if I ever have to do it again.

    I got my girlfriend a new Macbook Pro M1 for Hanukkah and she gave me her old one (It’s a Macbook Pro Mid 2012, or 14,1). I was going to update it to Mac OS 11, but found out that it didn’t support it, so I figured I would try to revive life to it by installing Ubuntu on it. This proved to be harder than I expected, but if you keep reading, I’ll tell you how I finally did it. (I’m actually writing this blog from the laptop running Ubuntu.)

    So, the installation was pretty straight forward. I burned Ubuntu 20.04.2 on a DVD (From https://releases.ubuntu.com) and booted up the mac by inserting the DVD in the drive and holding down the “Option” key while booting up and I select the first EFI Partition to boot from by pressing the Up arrow after selecting it. It booted right into Ubuntu no problem.

    I managed to install Ubuntu, and everything went smoothly. After installation, I noticed a weird error about MOK and EFI. I found out that Mac’s EFI wants a signed OS. To fix this, all I did was:

    sudo su -
cd /boot/efi/EFI/ubuntu
cp grubx64.efi shimx64.efi

    This will clear the black screen and error when booting.

    Next, I ran sudo apt update & sudo apt upgrade -y to make sure I had all the updates to my laptop.

    With the 20.04.2 update of Ubuntu, everything works out of the box with the Mid 2012 version of the Mac Book. If you run into any issues during the installation, leave a comment and I will try to help.

    Leave a comment if it helps.

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