Comment # 9 on bug 1035240 from andreas bittner

I removed the KOTD kernel, then booted (without the nomodeset parameter). The
display stays dark with displayport cable/ports in use.

Then I switched over while system running, to hdmi cable, then ctrl-alt-f1 or
something, brings the "text mode" like logon with the hdmi cable.


modinfo shows:

modinfo radeon | grep file
filename:      
/lib/modules/4.4.57-18.3-default/weak-updates/updates/drivers/gpu/drm/radeon/radeon.ko


checkin the files shows that they are identical to your installed/built file:

# sha256sum
/lib/modules/4.4.57-18.3-default/weak-updates/updates/drivers/gpu/drm/radeon/radeon.ko
2b373da6496efceef83790b06cf5172553f5304a0a47bf12e90518a534e56efd 
/lib/modules/4.4.57-18.3-default/weak-updates/updates/drivers/gpu/drm/radeon/radeon.ko

# sha256sum
/lib/modules/4.4.27-2-default/updates/drivers/gpu/drm/radeon/radeon.ko 
2b373da6496efceef83790b06cf5172553f5304a0a47bf12e90518a534e56efd 
/lib/modules/4.4.27-2-default/updates/drivers/gpu/drm/radeon/radeon.ko



So the system uses your radeon.ko file, but still fails to produce proper
displayport link and pixels via displayport.