DRM leases + X: some tests

[Raimonds Cicans]

Hi!

TL;DR - "DRM leases + X" feature is broken, _AT_BEST_ you get only 2D
accelerated X slaves, in most cases X slave server wont start.


Tests:
In all tests monitors was connected directly to videocard.

PC1 (NOT systemd): Radeon R7 240 (Oland Pro)
    kernel (radeon) - mainX (radeon) - slaveX(radeon):
        slave X server refuses to start:
            (EE) RADEON(0): [drm] failed to set drm interface version.
            (EE) RADEON(0): Kernel modesetting setup failed

    kernel (radeon) - mainX (radeon) - slaveX(modesetting):
    kernel (radeon) - mainX (modesetting) - slaveX(modesetting):
        slave X server refuses to start:
            (WW) modeset(0): No outputs definitely connected, trying
again...
            (WW) modeset(0): Unable to find connected outputs - setting
1024x768 initial framebuffer
            (EE) modeset(0): No modes.


    kernel (amdgpu) - mainX (amdgpu) - slaveX(amdgpu):
        slave X server refuses to load amdgpu driver

    kernel (amdgpu) - mainX (amdgpu) - slaveX(modesetting):
    kernel (amdgpu) - mainX (modesetting) - slaveX(modesetting):
            (WW) modeset(0): No outputs definitely connected, trying
again...
            (WW) modeset(0): Unable to find connected outputs - setting
1024x768 initial framebuffer
            (EE) modeset(0): No modes.


PC2 (systemd):
    Radeon RX 580:
        kernel (amdgpu) - mainX (amdgpu) - slaveX (amdgpu)
            slave X server refuses to load amdgpu driver

        kernel (amdgpu) - mainX (amdgpu) - slaveX (modesetting)
        kernel (amdgpu) - mainX (modesetting) - slaveX (modesetting)
            works. Only 2D acceleration

    HD Graphics 530:
        kernel (intel) - mainX (intel) - slaveX (intel)
        kernel (intel) - mainX (intel) - slaveX (modesetting)
            xlease fails to open lease

        kernel (intel) - mainX (modesetting) - slaveX (modesetting)
            System starts without errors, but there is no image on
monitor (even on mainX)


Misc:

Strange behaviour in Radeon RX 580 working configuration:

1) if I run all commands from command line by hands, then system starts
but I get black screen. If I run same commands by python script, then
all works normally

2) when I close X application sometime slave X server crashes

3) if I connect video card to KVM switch and switch outputs several
times, then when I close X application almost always slave X server crashes

Strange behaviour if slave X server started without "-seat" parameter:
- in some configurations slave X server tries to take over card and
throw away master X server
- in some configurations slave X server do not start (message "No
outputs...")


For Jesus sake why every driver (kernel & X) have its own opinion how to
call outputs on same card???


Etc... etc... etc...



Raimonds Cicans