Arch Linux

Ashark

Member

Registered: 2017-06-01

Posts: 31

Reverse prime with Intel + Amd on a laptop

I have a laptop with amd hybrid graphics (intel i7-4500U + amd R7 M265).
I am trying to make a setup when an amd gpu acts as a primary gpu, while intel is used for output.
Here is exactly my question, but it has no solution there. I have made such a config with edited PCI ids:

Section "ServerLayout"
    Identifier "layout"
    Screen 0 "amdgpu"
    Inactive "Intel"
EndSection

Section "Device"
    Identifier  "amdgpu"
    Driver      "amdgpu"
    BusID       "PCI:3:0:0" # my laptop
    # BusID    "PCI:1:0:0" # my desktop
EndSection

Section "Screen"
    Identifier "amdgpu"
    Device "amdgpu"
EndSection

Section "Device"
    Identifier  "Intel"
    Driver      "Intel"
    BusID       "PCI:0:2:0"  # my laptop, the same for my desktop
EndSection

Section "Screen"
    Identifier "Intel"
    Device "Intel"
EndSection

And I have

xrandr --setprovideroutputsource 0 1 # also tried swapping 0 and 1
xrandr --auto

in my /usr/share/sddm/scripts/Xsetup.

But when I reboot a laptop, I am stucked at Reached target Graphical interface.
In /var/log/Xorg.0.log I see these strings that I think are relevant:

(EE) AMDGPU(0): No modes.
...
(EE) Screen(s) found, but none have a usable configuration
Fatal server error 
(EE) no screens found(EE)

Also I should note that I am booting with radeon.si_support=0 amdgpu.si_support=1 kernel parameters to activate amdgpu instead of radeon kernel driver for my amd R7 M265.

What I am doing wrong?

I also tried to recreate such setup (intel primary gpu set in bios with attached monitor and amd gpu as secondary without attached monitors) on a desktop. It is the same installation drive, but with edited PCI ids for desktop. And it actually worked. glxinfo | grep "renderer string" said that it is amd, while monitor is attached to intel. (But it has a very huge displaying lag, do not know why).

And this all is going with opensource amdgpu driver.