Display is wrong resolution, aspect ratio, and size

[Fletcher Porter]

So last night (April 13th), I installed an update from Canonical that popped up in a GUI, it said something about a security update (I didn't look at it too hard). Since then I've rebooted my machine and now the display is the wrong resolution (it ought to be 3840 x 2160, 597mm x 336mm, 60fps [monitor](https://www.lg.com/us/monitors/lg-27UD58-B-4k-uhd-led-monitor)). I'm presently on Ubuntu 20.04.2 LTS.

```
$ xrandr
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1024 x 768, current 1024 x 768, maximum 1024 x 768
default connected primary 1024x768+0+0 0mm x 0mm
   1024x768 76.00*
```

```
$ inxi -G
Graphics:
  Device-1: NVIDIA GM107GL [Quadro K2200] driver: N/A
  Display: x11 server: X.Org 1.20.9 driver: fbdev,nouveau
  unloaded: modesetting,vesa resolution: 1024x768~76Hz
  OpenGL: renderer: llvmpipe (LLVM 11.0.0 256 bits) v: 4.5 Mesa 20.2.6
```

I've tried unplugging and replugging the monitor, rebooting several times, adding an xrandr modeline, and changing `/etc/default/grub` to have `GRUB_CMDLINE_LINUX_DEFAULT="quiet splash i915.alpha_support=1"` (where it was `"quiet splash"` before). None of these have led to any success.

My feeling is that there's some graphics driver issue (that the renderer is llvmpipe doesn't seem right).

I guess there's also a confounding factor in that I'm running the display through a [KVM switch](https://www.tripplite.com/2-port-displayport-usb-kvm-switch-4k-60-hz-hdr%7EB005DPUA4), but I really hope that's not the problem. I've been using it for a while anyway with no issue, the Windows 10 partition of this machine renders fine, and I have another machine running 18.04 that gets the resolution just fine.

I tried booting into recovery mode, which was no dice (also tried cleaning up `dpkg` through the recovery interface). While I was in the GRUB menu, I noticed that it defaults to the kernel version 5.8.0-49, but that I also had 5.8.0-48 installed. Boothing into the older kernel, everything worked. Curious, I checked the logs.

```
$ cat /var/log/dpkg.log | grep linux-image
2021-04-13 23:15:01 install linux-image-5.8.0-49-generic:amd64 <none> 5.8.0-49.55~20.04.1
```

And that lines up with when I did that update. So it seems that the new kernel version somehow made it so xrandr couldn't detect any of the modes on my monitor and just defaulted to some default.

So the workaround presently is just boot with 5.8.0-48.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: xorg 1:7.7+19ubuntu14
ProcVersionSignature: Ubuntu 5.8.0-49.55~20.04.1-generic 5.8.18
Uname: Linux 5.8.0-49-generic x86_64
.tmp.unity_support_test.1:

ApportVersion: 2.20.11-0ubuntu27.16
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CasperMD5CheckResult: skip
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Wed Apr 14 17:21:08 2021
DistUpgraded: Fresh install
DistroCodename: focal
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, including running git bisection searches
GraphicsCard:
 NVIDIA Corporation GM107GL [Quadro K2200] [10de:13ba] (rev a2) (prog-if 00 [VGA controller])
   Subsystem: NVIDIA Corporation GM107GL [Quadro K2200] [10de:1097]
InstallationDate: Installed on 2021-02-15 (58 days ago)
InstallationMedia: Ubuntu 20.04.2.0 LTS "Focal Fossa" - Release amd64 (20210209.1)
MachineType: Gigabyte Technology Co., Ltd. X570 AORUS ELITE WIFI
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.8.0-49-generic root=UUID=babb99d2-0867-4673-b5ec-2cce0643eaa2 ro quiet splash i915.alpha_support=1 vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/15/2020
dmi.bios.release: 5.17
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: F30
dmi.board.asset.tag: Default string
dmi.board.name: X570 AORUS ELITE WIFI
dmi.board.vendor: Gigabyte Technology Co., Ltd.
dmi.board.version: x.x
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 3
dmi.chassis.vendor: Default string
dmi.chassis.version: Default string
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrF30:bd09/15/2020:br5.17:svnGigabyteTechnologyCo.,Ltd.:pnX570AORUSELITEWIFI:pvr-CF:rvnGigabyteTechnologyCo.,Ltd.:rnX570AORUSELITEWIFI:rvrx.x:cvnDefaultstring:ct3:cvrDefaultstring:
dmi.product.family: X570 MB
dmi.product.name: X570 AORUS ELITE WIFI
dmi.product.sku: Default string
dmi.product.version: -CF
dmi.sys.vendor: Gigabyte Technology Co., Ltd.
version.compiz: compiz 1:0.9.14.1+20.04.20200211-0ubuntu1
version.libdrm2: libdrm2 2.4.102-1ubuntu1~20.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 20.2.6-0ubuntu0.20.04.1
version.libgl1-mesa-glx: libgl1-mesa-glx N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.20.9-2ubuntu1.2~20.04.2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20200226-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.16-1

[Daniel van Vugt (vanvugt)]

It appears you have a manually installed Nvidia driver, which is not supported, and it stopped working around the time of the kernel update from 5.8.0-48 to 5.8.0-49.

Please uninstall the NVIDIA driver you have and in future only install NVIDIA drivers using the 'Additional Drivers' app so as to ensure they will keep working with future kernel updates.

[Fletcher Porter (fpdotmonkey)]

Ok yeah this was it. xrandr is getting all the expected modelines now on kernel 5.8.0-49-generic. Thank you very much!