Multiple AMD GPU in desktop - wrong primary GPU

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1

I installed a second AMD video card in my desktop running Fedora 37 (Kinoite). I have it set up as follows:

PCIe Slot 1: RX6900XT → monitor plugged into DP
PCIe Slot 5: RX6400 → no outputs connected

I’m experiencing a couple issues, though I think they’re related.

  1. Although I have my monitor connected to the RX6900XT card, I can see using radeontop and rocm-smi that the RX6400 is doing all the rendering. How do I change this so that the RX6900XT is the primary GPU?

612c797214c3ff60dbd08ed28159930c34002765.png
612c797214c3ff60dbd08ed28159930c34002765.png918×251 22.9 KB

  1. Probably related to this, but sddm does not show up on my monitor. After the Fedora boot splash, it just goes to black screen - no signal detected. I can manually change TTY, login, and startplasma-wayland and it works.
lspci Info 
00:00.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Starship/Matisse Root Complex
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
00:00.2 IOMMU: Advanced Micro Devices, Inc. [AMD] Starship/Matisse IOMMU
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
00:01.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Host Bridge
00:01.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Starship/Matisse GPP Bridge
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
        Kernel driver in use: pcieport
00:01.2 PCI bridge: Advanced Micro Devices, Inc. [AMD] Starship/Matisse GPP Bridge
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
        Kernel driver in use: pcieport
00:02.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Host Bridge
00:03.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Host Bridge
00:03.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Starship/Matisse GPP Bridge
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
        Kernel driver in use: pcieport
00:04.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Host Bridge
00:05.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Host Bridge
00:07.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Host Bridge
00:07.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Starship/Matisse Internal PCIe GPP Bridge 0 to bus[E:B]
        Subsystem: Device 7c35:1462
        Kernel driver in use: pcieport
00:08.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Host Bridge
00:08.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Starship/Matisse Internal PCIe GPP Bridge 0 to bus[E:B]
        Subsystem: Device 7c35:1462
        Kernel driver in use: pcieport
00:14.0 SMBus: Advanced Micro Devices, Inc. [AMD] FCH SMBus Controller (rev 61)
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
        Kernel driver in use: piix4_smbus
        Kernel modules: i2c_piix4, sp5100_tco
00:14.3 ISA bridge: Advanced Micro Devices, Inc. [AMD] FCH LPC Bridge (rev 51)
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
00:18.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Matisse/Vermeer Data Fabric: Device 18h; Function 0
00:18.1 Host bridge: Advanced Micro Devices, Inc. [AMD] Matisse/Vermeer Data Fabric: Device 18h; Function 1
00:18.2 Host bridge: Advanced Micro Devices, Inc. [AMD] Matisse/Vermeer Data Fabric: Device 18h; Function 2
00:18.3 Host bridge: Advanced Micro Devices, Inc. [AMD] Matisse/Vermeer Data Fabric: Device 18h; Function 3
        Kernel driver in use: k10temp
        Kernel modules: k10temp
00:18.4 Host bridge: Advanced Micro Devices, Inc. [AMD] Matisse/Vermeer Data Fabric: Device 18h; Function 4
00:18.5 Host bridge: Advanced Micro Devices, Inc. [AMD] Matisse/Vermeer Data Fabric: Device 18h; Function 5
00:18.6 Host bridge: Advanced Micro Devices, Inc. [AMD] Matisse/Vermeer Data Fabric: Device 18h; Function 6
00:18.7 Host bridge: Advanced Micro Devices, Inc. [AMD] Matisse/Vermeer Data Fabric: Device 18h; Function 7
01:00.0 Non-Volatile memory controller: Phison Electronics Corporation E16 PCIe4 NVMe Controller (rev 01)
        Subsystem: Phison Electronics Corporation E16 PCIe4 NVMe Controller
        Kernel driver in use: nvme
        Kernel modules: nvme
20:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Matisse Switch Upstream
        Kernel driver in use: pcieport
21:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Matisse PCIe GPP Bridge
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
        Kernel driver in use: pcieport
21:01.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Matisse PCIe GPP Bridge
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
        Kernel driver in use: pcieport
21:02.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Matisse PCIe GPP Bridge
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
        Kernel driver in use: pcieport
21:05.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Matisse PCIe GPP Bridge
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
        Kernel driver in use: pcieport
21:08.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Matisse PCIe GPP Bridge
        Subsystem: Device 7c35:1462
        Kernel driver in use: pcieport
21:09.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Matisse PCIe GPP Bridge
        Subsystem: Device 7c35:1462
        Kernel driver in use: pcieport
21:0a.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Matisse PCIe GPP Bridge
        Subsystem: Device 7c35:1462
        Kernel driver in use: pcieport
22:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd NVMe SSD Controller SM981/PM981/PM983
        Subsystem: Samsung Electronics Co Ltd SSD 970 EVO Plus 1TB
        Kernel driver in use: nvme
        Kernel modules: nvme
23:00.0 Non-Volatile memory controller: Phison Electronics Corporation E12 NVMe Controller (rev 01)
        Subsystem: Phison Electronics Corporation E12 NVMe Controller
        Kernel driver in use: nvme
        Kernel modules: nvme
24:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] Navi 10 XL Upstream Port of PCI Express Switch (rev c7)
        Kernel driver in use: pcieport
25:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] Navi 10 XL Downstream Port of PCI Express Switch
        Subsystem: Advanced Micro Devices, Inc. [AMD/ATI] Navi 10 XL Downstream Port of PCI Express Switch
        Kernel driver in use: pcieport
26:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Navi 24 [Radeon RX 6400/6500 XT/6500M] (rev c7)
        Subsystem: Hewlett-Packard Company Device 8a52
        Kernel driver in use: amdgpu
        Kernel modules: amdgpu
26:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Navi 21/23 HDMI/DP Audio Controller
        Subsystem: Advanced Micro Devices, Inc. [AMD/ATI] Navi 21/23 HDMI/DP Audio Controller
        Kernel driver in use: snd_hda_intel
        Kernel modules: snd_hda_intel
27:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8125 2.5GbE Controller
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
        Kernel driver in use: r8169
        Kernel modules: r8169
2a:00.0 Non-Essential Instrumentation [1300]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse Reserved SPP
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
2a:00.1 USB controller: Advanced Micro Devices, Inc. [AMD] Matisse USB 3.0 Host Controller
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
        Kernel driver in use: xhci_hcd
2a:00.3 USB controller: Advanced Micro Devices, Inc. [AMD] Matisse USB 3.0 Host Controller
        Subsystem: Advanced Micro Devices, Inc. [AMD] Device 148c
        Kernel driver in use: xhci_hcd
2b:00.0 SATA controller: Advanced Micro Devices, Inc. [AMD] FCH SATA Controller [AHCI mode] (rev 51)
        Subsystem: Advanced Micro Devices, Inc. [AMD] FCH SATA Controller [AHCI mode]
        Kernel driver in use: ahci
2c:00.0 SATA controller: Advanced Micro Devices, Inc. [AMD] FCH SATA Controller [AHCI mode] (rev 51)
        Subsystem: Advanced Micro Devices, Inc. [AMD] FCH SATA Controller [AHCI mode]
        Kernel driver in use: ahci
2d:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] Navi 10 XL Upstream Port of PCI Express Switch (rev c0)
        Kernel driver in use: pcieport
2e:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] Navi 10 XL Downstream Port of PCI Express Switch
        Subsystem: Advanced Micro Devices, Inc. [AMD/ATI] Navi 10 XL Downstream Port of PCI Express Switch
        Kernel driver in use: pcieport
2f:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Navi 21 [Radeon RX 6800/6800 XT / 6900 XT] (rev c0)
        Subsystem: XFX Limited Speedster MERC 319 AMD Radeon RX 6900 XT Black
        Kernel driver in use: amdgpu
        Kernel modules: amdgpu
2f:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Navi 21/23 HDMI/DP Audio Controller
        Subsystem: Advanced Micro Devices, Inc. [AMD/ATI] Navi 21/23 HDMI/DP Audio Controller
        Kernel driver in use: snd_hda_intel
        Kernel modules: snd_hda_intel
2f:00.2 USB controller: Advanced Micro Devices, Inc. [AMD/ATI] Device 73a6
        Subsystem: Advanced Micro Devices, Inc. [AMD/ATI] Device 73a6
        Kernel driver in use: xhci_hcd
2f:00.3 Serial bus controller: Advanced Micro Devices, Inc. [AMD/ATI] Navi 21 USB
        Subsystem: Advanced Micro Devices, Inc. [AMD/ATI] Device 0408
        Kernel driver in use: i2c-designware-pci
30:00.0 Non-Essential Instrumentation [1300]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Function
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
31:00.0 Non-Essential Instrumentation [1300]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse Reserved SPP
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
31:00.3 USB controller: Advanced Micro Devices, Inc. [AMD] Matisse USB 3.0 Host Controller
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7c35
        Kernel driver in use: xhci_hcd
31:00.4 Audio device: Advanced Micro Devices, Inc. [AMD] Starship/Matisse HD Audio Controller
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device cc35
        Kernel driver in use: snd_hda_intel
        Kernel modules: snd_hda_intel
2

Do you get the same device for:
DRI_PRIME=1 glxinfo | grep Device
DRI_PRIME=0 glxinfo | grep Device

For SDDM can you check:
systemctl status display-manager.service
journalctl -b -u sddm.service

3

I get the different devices when I run those:

> DRI_PRIME=1 glxinfo | grep Device      
    Device: AMD Radeon RX 6900 XT (navi21, LLVM 15.0.0, DRM 3.48, 6.0.10-300.fc37.x86_64) (0x73bf)
> DRI_PRIME=0 glxinfo | grep Device
    Device: AMD Radeon RX 6400 (navi24, LLVM 15.0.0, DRM 3.48, 6.0.10-300.fc37.x86_64) (0x743f)
4

As for the SDDM problem, I think I was correct in assuming that the issue is linked. It seems that SDDM is outputting to the default display (RX6400), even though the monitor is plugged into the RX6900 XT.

I forced the output to the correct display by following this guide to set the primary display in /etc/sddm/Xsetup and it worked. Though problem #1 still remained - everything was still being rendered on the RX6400 and the framebuffer was being sent to the RX6900 XT to the monitor.

1 Like
5

You could install switcheroo-control which would give you the option to choose which card you’re running with.

You could try adding export DRI_PRIME=1 to your users .bashrc file (assuming you’re using bash)

You could try setting it globally by adding DRI_PRIME=1 to /etc/environment

You can also individually modify desktop files to use a certain gpu.

1 Like