System keeps briefly freezing with kernel errors "snd_hda_intel 0000:01:00.1: Disabling via vga_switcheroo" and "snd_hda_intel 0000:01:00.1: Cannot lock devices!"

When using Wayland, I observe sub-second freezes a couple of times per minute.
It just freezes the mouse and everything for a split second, and continues as if nothing happened.
When using Xorg, everything runs smoothly. (hence I did not pick Xorg in ubuntu-bug)

I suspect this is a GPU issue.
My laptop has a hybrid GPU, and dmesg is filled with vga_switcheroo messages

[ 2640.943598] snd_hda_intel 0000:01:00.1: Disabling via vga_switcheroo
[ 2641.243870] snd_hda_intel 0000:01:00.1: Cannot lock devices!
[ 2641.260536] ACPI: \_SB_.PCI0.PEG0.VID_: failed to evaluate _DSM
[ 2658.996392] snd_hda_intel 0000:01:00.1: Enabling via vga_switcheroo

I tried to manually switch to the dedicated graphics card, and that completely froze my session.
Now I can't even log in using Wayland anymore, as it straight up crashes and goes back to the login screen.
Xorg is still fine...

Now there are other weird messages such as
[ 2777.002437] nouveau 0000:01:00.0: gr: DATA_ERROR 0000009c [] ch 8 [001f998000 systemd-logind[855]] subc 0 class 9297 mthd 0d78 data 00000004
[ 2889.648718] snd_hda_codec_hdmi hdaudioC1D0: out of range cmd 0:5:707:ffffffff

And I suppose these are from the crash that I caused myself (not sure if related to the short freezes)
[ 2551.513519] gnome-shell[5179]: segfault at 128 ip 00007f409effeab0 sp 00007ffcf4af1148 error 4 in libmutter-clutter-2.so[7f409efba000+161000]
[ 2570.239129] Chrome_~dThread[6018]: segfault at 0 ip 00007ff90a3494cd sp 00007ff9086c9b00 error 6 in libxul.so[7ff90958f000+6111000]
[ 2628.443468] gnome-shell[6348]: segfault at 0 ip 00007f6349eb6c90 sp 00007ffe5acd8bc8 error 4 in libgbm.so.1.0.0[7f6349eb4000+c000]
[ 2777.424194] gnome-shell[6913]: segfault at 0 ip 00007ff1e8550c90 sp 00007ffe6cddb228 error 4 in libgbm.so.1.0.0[7ff1e854e000+c000]

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gnome-shell 3.28.1-0ubuntu2
ProcVersionSignature: Ubuntu 4.15.0-22.24-generic 4.15.17
Uname: Linux 4.15.0-22-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.1
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Tue Jun 5 08:14:17 2018
DisplayManager: gdm3
GsettingsChanges:
 b'org.gnome.shell' b'command-history' redacted by apport
 b'org.gnome.shell' b'app-picker-view' b'uint32 1'
 b'org.gnome.shell' b'favorite-apps' redacted by apport
 b'org.gnome.desktop.interface' b'gtk-im-module' b"'gtk-im-context-simple'"
InstallationDate: Installed on 2018-04-27 (38 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
SourcePackage: gnome-shell
UpgradeStatus: No upgrade log present (probably fresh install)
---
ApportVersion: 2.20.9-0ubuntu7.1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: pepijn 1259 F.... pulseaudio
CurrentDesktop: ubuntu:GNOME
DistroRelease: Ubuntu 18.04
InstallationDate: Installed on 2018-04-27 (38 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
MachineType: Dell Inc. Latitude E6420
Package: linux (not installed)
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-22-generic root=UUID=0bfd26c3-7ff7-4c73-8c5b-aaeca648e5f3 ro quiet splash vt.handoff=1
ProcVersionSignature: Ubuntu 4.15.0-22.24-generic 4.15.17
RelatedPackageVersions:
 linux-restricted-modules-4.15.0-22-generic N/A
 linux-backports-modules-4.15.0-22-generic N/A
 linux-firmware 1.173.1
Tags: bionic
Uname: Linux 4.15.0-22-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dialout dip lpadmin plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 01/04/2016
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A23
dmi.board.name: 032T9K
dmi.board.vendor: Dell Inc.
dmi.board.version: A01
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA23:bd01/04/2016:svnDellInc.:pnLatitudeE6420:pvr01:rvnDellInc.:rn032T9K:rvrA01:cvnDellInc.:ct9:cvr:
dmi.product.name: Latitude E6420
dmi.product.version: 01
dmi.sys.vendor: Dell Inc.