Also known as, "How To Learn The Hard Way"
Despite reading numerous posts and articles about problems using the proprietary AMD drivers for Radeon graphics cards, I tried to pretend they didn't apply to me.
I dropped an inexpensive R7 250 card into my machine. Was doing other work at the time (transferring install to an SSD), I let Kubuntu install whatever drivers it deemed appropriate. Performance was fine. Not stunningly different than the onboard AMD graphics.
So I went to the Radeon site and got the latest driver. I ignored the fact that it didn't mention anything higher than (K)Ubuntu 16.0.4 LTS. I attempted to install it.
And boy, it wrecked my system but good. A totally-glitched screen, either over direct VGA or remote (headless) HDMI. Unusable. I tried to SSH my way in and undo the damage. The "uninstall" script AMD mentioned didn't exist. I tried to reinstall the open source driver. I finally added "nomodeset" to GRUB and got the thing booted at 640x480. Plasma5 doesn't fit well on a 640x480 screen.
But once I was in, I ran a massive rsync job to transfer my "home" directory to my secondary drive. Be thankful for large media-storage drives: you can totally rsync your cluttered ~ directory to it.
Reinstall Kubuntu. Nice to have an SSD boot disk: installed in only about 10 minutes. Rsync back took about a half hour.
So take this as a warning: learn from your elders (even though I'm a graybeard myself) and don't fool with drivers that are questionable for your system.
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Sidenote: After reinstalling, I was noticing high RAM use (thanks to a system monitor plasmoid). The top offender was Xorg, chewing through more than a quarter of my 12GB of memory. I checked the kernel modules to see what driver I was actually using, and it was the open source "radeon" module, although the "amdgpu" module was present as well. I blacklisted the radeon module and my RAM hasn't moved above half since. And I'm running with all the silly graphic transparency effects, the "animated 3D cube" transition between virtual desktops (each with a different Clash wallpaper), etc. RAM didn't even get chewed up when I was compiling Plasma/KF5 source packages.
Moral of the story: use the right driver for the right job.
Despite reading numerous posts and articles about problems using the proprietary AMD drivers for Radeon graphics cards, I tried to pretend they didn't apply to me.
I dropped an inexpensive R7 250 card into my machine. Was doing other work at the time (transferring install to an SSD), I let Kubuntu install whatever drivers it deemed appropriate. Performance was fine. Not stunningly different than the onboard AMD graphics.
So I went to the Radeon site and got the latest driver. I ignored the fact that it didn't mention anything higher than (K)Ubuntu 16.0.4 LTS. I attempted to install it.
And boy, it wrecked my system but good. A totally-glitched screen, either over direct VGA or remote (headless) HDMI. Unusable. I tried to SSH my way in and undo the damage. The "uninstall" script AMD mentioned didn't exist. I tried to reinstall the open source driver. I finally added "nomodeset" to GRUB and got the thing booted at 640x480. Plasma5 doesn't fit well on a 640x480 screen.
But once I was in, I ran a massive rsync job to transfer my "home" directory to my secondary drive. Be thankful for large media-storage drives: you can totally rsync your cluttered ~ directory to it.
Reinstall Kubuntu. Nice to have an SSD boot disk: installed in only about 10 minutes. Rsync back took about a half hour.
So take this as a warning: learn from your elders (even though I'm a graybeard myself) and don't fool with drivers that are questionable for your system.
---
Sidenote: After reinstalling, I was noticing high RAM use (thanks to a system monitor plasmoid). The top offender was Xorg, chewing through more than a quarter of my 12GB of memory. I checked the kernel modules to see what driver I was actually using, and it was the open source "radeon" module, although the "amdgpu" module was present as well. I blacklisted the radeon module and my RAM hasn't moved above half since. And I'm running with all the silly graphic transparency effects, the "animated 3D cube" transition between virtual desktops (each with a different Clash wallpaper), etc. RAM didn't even get chewed up when I was compiling Plasma/KF5 source packages.
Moral of the story: use the right driver for the right job.
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