On Wed, Nov 9, 2022 at 6:09 PM Patrick O'Callaghan
<pocallaghan(a)gmail.com> wrote:
I've replaced my ageing Nvidia card with a more recent and much faster
AMD GPU. However when I boot the system, the default display still
shows as the built-in Intel chip, even though AMD modules are loaded:
$ sudo lsmod|grep -i amd
amdgpu 10153984 1
iommu_v2 24576 1 amdgpu
gpu_sched 49152 1 amdgpu
drm_ttm_helper 16384 1 amdgpu
drm_buddy 20480 2 amdgpu,i915
drm_display_helper 180224 2 amdgpu,i915
ttm 94208 3 amdgpu,drm_ttm_helper,i915
(Nvidia modules are not loaded).
Inxi shows:
$ inxi -G
Graphics:
Device-1: Intel IvyBridge GT2 [HD Graphics 4000] driver: i915 v: kernel
Device-2: AMD Ellesmere [Radeon RX 470/480/570/570X/580/580X/590]
driver: amdgpu v: kernel
Display: x11 server: X.Org v: 1.20.14 with: Xwayland v: 22.1.3 driver: X:
loaded: amdgpu,modesetting unloaded: fbdev,vesa dri: crocus gpu: i915
resolution: 1920x1080~60Hz
OpenGL: renderer: Mesa Intel HD Graphics 4000 (IVB GT2) v: 4.2 Mesa
22.1.7
Switcherooctl shows both GPUs:
$ switcherooctl list
Device: 0
Name: Intel® HD Graphics 4000
Default: yes
Environment: DRI_PRIME=pci-0000_00_02_0
Device: 1
Name: Advanced Micro Devices, Inc. [AMD®/ATI] Ellesmere
[Radeon RX 470/480/570/570X/580/580X/590] (Radeon RX 580)
Default: no
Environment: DRI_PRIME=pci-0000_01_00_0
I should mention that both GPUs are connected through an HDMI switch to
a single monitor. I've used this successfully in the past to get PCI
passthrough on Windows VMs for gaming.
I haven't touched anything else. I tried unplugging the i915 and
rebooting (after removing the HDMI switch and connecting the monitor
directly), but simply got a blank screen (in fact three dots at the top
left).
In order to disable i915 altogether, I used an option in bios/efi firmware.
(I have an NVIDIA card and want to use it always/for any application.)
Is there some grub magic I need to do? I assumed this would be
automatic but it seems not.
If the intention is to use either i915 or the AMD card depending on
the application
that is AMD Dynamic Switchable Graphics,
I would suggest looking at
https://wiki.archlinux.org/title/PRIME#Gnome_integration
https://wiki.archlinux.org/title/PRIME
https://wiki.archlinux.org/title/ATI
https://wiki.archlinux.org/title/AMDGPU
greg