Prime offloading with an external display directly connected to dGPU

syrok0010 · 2023-02-13 19:43:16

I have an Asus Rog Strix G15 Advantage Edition (G513QY).
Laptop has an HDMI port connected to iGPU and USB-C (Display port) connected to dGPU.
My external display (2k 165hz) is connected to USB-C.
When I play Dota 2 on Win 11 I get about 170 FPS (game is running on the external display with laptop lid opened).
The same set up on Arch gives me 90 FPS.
Connecting external display to HDMI gives +20 FPS (115 FPS on average).
Using only laptop display gives me Windows like performance (160 FPS on average).
I've read Arch Wiki on Hybrid graphics (Prime specifically).
I use DRI_PRIME=1 flag in Steam Dota startup options.
In theory, an external display connected to dGPU directly should give the best performance.
Any idea how to fix the issue?

Arch installed via archinstall.
DE: Plasma (Wayland)
All software is up to date.
Laptop has AMD CPU with integrated GPU + AMD discrete GPU.

Last edited by syrok0010 (2023-02-13 19:48:25)

Lone_Wolf · 2023-02-14 12:03:32

syrok0010 wrote:

Laptop has an HDMI port connected to iGPU and USB-C (Display port) connected to dGPU.
Laptop has AMD CPU with integrated GPU + AMD discrete GPU.

That confuses me .

Is the discrete gpu internal or external to the laptop ?

Welcome to archlinux forums

syrok0010 · 2023-02-14 14:45:15

dGPU is internal.
HDMI is connected to iGPU meaning that video rendered by dGPU should go via iGPU (dGPU -> iGPU -> HDMI). In this setup iGPU is a bottleneck. In theory and in Windows it shows lower performance than the one with USB-C.
USB-C is connected to dGPU. Video rendered by dGPU goes directly to USB-C (dGPU -> USB-C).

Last edited by syrok0010 (2023-02-14 14:47:35)

Lone_Wolf · 2023-02-15 10:02:02

USB-C is connected to dGPU. Video rendered by dGPU goes directly to USB-C (dGPU -> USB-C).

Arch wiki only mentions X for multihead, how did you configure it and verify that is how the connection works ?

Please post full outputs of

$ lspci -k
$ lsusb -tv

syrok0010 · 2023-02-15 14:46:14

As for multihead, I've researched a bit and as far as I am concerned multihead on wayland is managed by compositor: KWin in my case (tried both 5.26, 5.27). I configured it graphically via Plasma System Settings GUI.
As multihead is dependent on compositor I decided to try Mutter. And it was much better although still much worse than only laptop screen or Windows.
I don't know how to verify the direct connection. Any ideas? Asus claims the way it works is the way I described. Or at least it should work that way.

Upd: New plasma (5.27) is actually a downgrade in performance on USB-C config. Constant freezes and stutters.

The outputs you asked:

00:00.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir/Cezanne Root Complex
	Subsystem: ASUSTeK Computer Inc. Device 16c2
00:00.2 IOMMU: Advanced Micro Devices, Inc. [AMD] Renoir/Cezanne IOMMU
	Subsystem: ASUSTeK Computer Inc. Device 16c2
00:01.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir PCIe Dummy Host Bridge
00:01.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Renoir PCIe GPP Bridge
	Subsystem: ASUSTeK Computer Inc. Device 16c2
	Kernel driver in use: pcieport
00:02.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir PCIe Dummy Host Bridge
00:02.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Renoir/Cezanne PCIe GPP Bridge
	Subsystem: ASUSTeK Computer Inc. Device 16c2
	Kernel driver in use: pcieport
00:02.2 PCI bridge: Advanced Micro Devices, Inc. [AMD] Renoir/Cezanne PCIe GPP Bridge
	Subsystem: ASUSTeK Computer Inc. Device 16c2
	Kernel driver in use: pcieport
00:02.4 PCI bridge: Advanced Micro Devices, Inc. [AMD] Renoir/Cezanne PCIe GPP Bridge
	Subsystem: ASUSTeK Computer Inc. Device 16c2
	Kernel driver in use: pcieport
00:08.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir PCIe Dummy Host Bridge
00:08.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Renoir Internal PCIe GPP Bridge to Bus
	Subsystem: Advanced Micro Devices, Inc. [AMD] Renoir Internal PCIe GPP Bridge to Bus
	Kernel driver in use: pcieport
00:14.0 SMBus: Advanced Micro Devices, Inc. [AMD] FCH SMBus Controller (rev 51)
	Subsystem: ASUSTeK Computer Inc. Device 16c2
	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: ASUSTeK Computer Inc. Device 16c2
00:18.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Cezanne Data Fabric; Function 0
00:18.1 Host bridge: Advanced Micro Devices, Inc. [AMD] Cezanne Data Fabric; Function 1
00:18.2 Host bridge: Advanced Micro Devices, Inc. [AMD] Cezanne Data Fabric; Function 2
00:18.3 Host bridge: Advanced Micro Devices, Inc. [AMD] Cezanne Data Fabric; Function 3
	Kernel driver in use: k10temp
	Kernel modules: k10temp
00:18.4 Host bridge: Advanced Micro Devices, Inc. [AMD] Cezanne Data Fabric; Function 4
00:18.5 Host bridge: Advanced Micro Devices, Inc. [AMD] Cezanne Data Fabric; Function 5
00:18.6 Host bridge: Advanced Micro Devices, Inc. [AMD] Cezanne Data Fabric; Function 6
00:18.7 Host bridge: Advanced Micro Devices, Inc. [AMD] Cezanne Data Fabric; Function 7
01:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] Navi 10 XL Upstream Port of PCI Express Switch (rev c3)
	Kernel driver in use: pcieport
02:00.0 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
03:00.0 Display controller: Advanced Micro Devices, Inc. [AMD/ATI] Navi 22 [Radeon RX 6700/6700 XT/6750 XT / 6800M/6850M XT] (rev c3)
	Subsystem: ASUSTeK Computer Inc. Radeon RX 6800M
	Kernel driver in use: amdgpu
	Kernel modules: amdgpu
03:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Navi 21/23 HDMI/DP Audio Controller
	Subsystem: ASUSTeK Computer Inc. Device 16c2
	Kernel driver in use: snd_hda_intel
	Kernel modules: snd_hda_intel
04:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 15)
	Subsystem: ASUSTeK Computer Inc. Device 208f
	Kernel driver in use: r8169
	Kernel modules: r8169
05:00.0 Network controller: MEDIATEK Corp. MT7921 802.11ax PCI Express Wireless Network Adapter
	Subsystem: AzureWave Device 4680
	Kernel driver in use: mt7921e
	Kernel modules: mt7921e
06:00.0 Non-Volatile memory controller: Intel Corporation Device f1aa (rev 03)
	Subsystem: Intel Corporation Device 390f
	Kernel driver in use: nvme
	Kernel modules: nvme
07:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Cezanne [Radeon Vega Series / Radeon Vega Mobile Series] (rev c7)
	Subsystem: ASUSTeK Computer Inc. Radeon Vega 8
	Kernel driver in use: amdgpu
	Kernel modules: amdgpu
07:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Renoir Radeon High Definition Audio Controller
	Subsystem: ASUSTeK Computer Inc. Device 16c2
	Kernel driver in use: snd_hda_intel
	Kernel modules: snd_hda_intel
07:00.2 Encryption controller: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 10h-1fh) Platform Security Processor
	Subsystem: ASUSTeK Computer Inc. Device 16c2
	Kernel driver in use: ccp
	Kernel modules: ccp
07:00.3 USB controller: Advanced Micro Devices, Inc. [AMD] Renoir/Cezanne USB 3.1
	Subsystem: ASUSTeK Computer Inc. Device 201f
	Kernel driver in use: xhci_hcd
	Kernel modules: xhci_pci
07:00.4 USB controller: Advanced Micro Devices, Inc. [AMD] Renoir/Cezanne USB 3.1
	Subsystem: ASUSTeK Computer Inc. Device 201f
	Kernel driver in use: xhci_hcd
	Kernel modules: xhci_pci
07:00.5 Multimedia controller: Advanced Micro Devices, Inc. [AMD] ACP/ACP3X/ACP6x Audio Coprocessor (rev 01)
	Subsystem: ASUSTeK Computer Inc. Device 104f
	Kernel modules: snd_pci_acp3x, snd_rn_pci_acp3x, snd_pci_acp5x, snd_pci_acp6x, snd_acp_pci, snd_rpl_pci_acp6x, snd_pci_ps, snd_sof_amd_renoir, snd_sof_amd_rembrandt
07:00.6 Audio device: Advanced Micro Devices, Inc. [AMD] Family 17h/19h HD Audio Controller
	DeviceName: HD Audio Controller
	Subsystem: ASUSTeK Computer Inc. Device 104f
	Kernel driver in use: snd_hda_intel
	Kernel modules: snd_hda_intel
/:  Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 10000M
    ID 1d6b:0003 Linux Foundation 3.0 root hub
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/4p, 5000M
        ID 2109:0817 VIA Labs, Inc. 
/:  Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 480M
    ID 1d6b:0002 Linux Foundation 2.0 root hub
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/5p, 480M
        ID 2109:2817 VIA Labs, Inc. 
        |__ Port 1: Dev 4, If 0, Class=Human Interface Device, Driver=usbhid, 12M
            ID 258a:002a  
        |__ Port 1: Dev 4, If 1, Class=Human Interface Device, Driver=usbhid, 12M
            ID 258a:002a  
        |__ Port 2: Dev 5, If 0, Class=Human Interface Device, Driver=usbhid, 12M
            ID 046d:c092 Logitech, Inc. G102/G203 LIGHTSYNC Gaming Mouse
        |__ Port 2: Dev 5, If 1, Class=Human Interface Device, Driver=usbhid, 12M
            ID 046d:c092 Logitech, Inc. G102/G203 LIGHTSYNC Gaming Mouse
        |__ Port 5: Dev 6, If 0, Class=, Driver=, 480M
            ID 2109:8886 VIA Labs, Inc. 
    |__ Port 4: Dev 3, If 0, Class=Wireless, Driver=btusb, 480M
        ID 13d3:3563 IMC Networks 
    |__ Port 4: Dev 3, If 1, Class=Wireless, Driver=btusb, 480M
        ID 13d3:3563 IMC Networks 
    |__ Port 4: Dev 3, If 2, Class=Wireless, Driver=, 480M
        ID 13d3:3563 IMC Networks 
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 10000M
    ID 1d6b:0003 Linux Foundation 3.0 root hub
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 480M
    ID 1d6b:0002 Linux Foundation 2.0 root hub
    |__ Port 3: Dev 2, If 0, Class=Human Interface Device, Driver=usbhid, 12M
        ID 0b05:1866 ASUSTek Computer, Inc.

Last edited by syrok0010 (2023-02-15 15:37:08)

Lone_Wolf · 2023-02-16 09:12:47

Did some searching and it appears this laptop is not exactly a standard hybrid graphics system, but uses a custom design with the usb-c port connected directly to the discrete card as you mentioned. https://gitlab.freedesktop.org/drm/amd/-/issues/1748 gave a lot of info about that design.

Your integrated gpu is the radeon vega 8, while the RX 6800M is the discrete gpu .

What is brand & model of the external monitor and usb-c to DP cable you use ?

syrok0010 · 2023-02-16 14:31:09

Thanks for the link. Looked through it. Seems that there is definitely a solution for X11. Although hasn't seen anything on Wayland. I will try to tinker with radeontop later today.
As for external monitor I use Gigabyte M27Q-P and USB-C to DP cable by VCOM.

Upd: Tried fixes from the thread and there are some issues too. Setting dGPU as primary in X config worked (I get Windows-like performance) but for some reason the mouse and keyboard connected to laptop through USB hub in monitor turn off by themselves.
Upd 2: The X fix works on Wayland too except the game crashes Plasma on leave and I guess making the dGPU primary lowers the time on battery power. Does making dGPU primary for X make it primary for Wayland? And where is config for GPUs on Wayland?
Upd 3: Although I get good performance randomly I get crashes, have to force reboot.
Upd 4: The X fix does not work on battery. Have to move config file from etc from tty to make SDDM start.

Last edited by syrok0010 (2023-02-17 15:25:26)

Arch Linux

#1 2023-02-13 19:43:16

Prime offloading with an external display directly connected to dGPU

#2 2023-02-14 12:03:32

Re: Prime offloading with an external display directly connected to dGPU

#3 2023-02-14 14:45:15

Re: Prime offloading with an external display directly connected to dGPU

#4 2023-02-15 10:02:02

Re: Prime offloading with an external display directly connected to dGPU

#5 2023-02-15 14:46:14

Re: Prime offloading with an external display directly connected to dGPU

#6 2023-02-16 09:12:47

Re: Prime offloading with an external display directly connected to dGPU

#7 2023-02-16 14:31:09

Re: Prime offloading with an external display directly connected to dGPU

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