GPU Passthrough Broke Everything Everywhere Visually

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GPU Passthrough Broke Everything Everywhere Visually

Post by Dorma » Mon Sep 24, 2018 1:02 am

This is an issue I'm critically stumped on right now, as it's a showstopper for my entire system. I don't often register to request help, but I need to get this fixed as soon as possible and I don't want to install a fresh copy of Linux Mint yet again with the potential of another failure. I've been fighting this for the past day and a half now.

Some background: I've built a PC with the intention of running Linux full-time and Windows 10 when I need it. I need Windows for games, Unity3D (Linux builds can't do what I need, long story), and various other things Linux might not have full support for. Due to the nature of this stuff, I have 16GB RAM with two graphics cards: an Nvidia GTX 1050 ti, which is the primary card for Linux, and an AMD Radeon RX 580, which is to run for Windows with passthrough. ... ssthrough/ is the guide I've been using. Things were going well until I got to Part 9 – Check Configuration and checked if vfio had binded my 580 properly. It did not, and upon checking my grub setup, where I block both AMD drivers, I realized I typo'd "amdgpu" as "amdgp". I changed this so "amdgpu" and "radeon" were to be blocked, updated grub, and rebooted. After the Mint logo, when the login screen would normally appear, I get No Signal messages on my two monitors and nothing shows.

First off, I'm already very confused because my primary graphics card on my motherboard is set to be PCIe slot 2 (1050 ti) and both monitors are wired to that. PCIe Slot 1 (AMD 580) has no monitors plugged in. I don't know video hardware and driver shenanigans very well, so I would assume this would just use Nvidia's drivers (and they did, according to the driver manager). Why this has caused a complete video meltdown is beyond me.

My attempt to fix this was to change the grub entry before booting by removing the blacklists for radeon and amdgpu. This decided to not work and I have no idea why. To try pushing it further, I went to recovery mode, rebuilt grub with those changes, and undid the vfio stuff for initramfs. This has still resulted in failure to display anything past the Mint logo.

This is my main computer, and I'd like to get this fixed as soon as possible, though I'm not sure how many people around here do this stuff at a level they can swoop in. I have a laptop to work on things if I absolutely must beforehand, but it's very weak and not practical for what I do. If there's any way to get back my login screen and properly pass through this card, I'd like to know what I'm doing wrong.

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Re: GPU Passthrough Broke Everything Everywhere Visually

Post by powerhouse » Mon Oct 29, 2018 7:35 am

Sorry I just saw your post now. I very much hope that you were able to solve the issue quickly.

" primary graphics card on my motherboard is set to be PCIe slot 2 (1050 ti) and both monitors are wired to that. PCIe Slot 1 (AMD 580) has no monitors..."

The first thing I would check is the BIOS settings. There should be somewhere a BIOS entry for the graphics card / slot to boot with. It is probably set to PCIe slot 1, but in your case it should be slot 2.
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