https://bugzilla.kernel.org/show_bug.cgi?id=200695
Lukas Fink (lukas.fink1@gmail.com) changed:
What |Removed |Added ---------------------------------------------------------------------------- CC| |lukas.fink1@gmail.com
--- Comment #43 from Lukas Fink (lukas.fink1@gmail.com) --- (In reply to babgozd from comment #38)
I am following this thread since it has created. My R9 380 with DVI-I output is connected to my VGA monitor with DVI-I male to VGA female adapter and I am getting black/blank screen while booting with amdgpu.dc=1 which is default since kernel 4.17. It is fine with amdgpu.dc=0. I can provide logs too if any kernel contributor wants to investigate the problem any further.
To me it seems, as if the DVI-I port is somehow misdetected/misconfigured as a DVI-D port. With dc=0 I find the files "card1-DVI-I-1" and "card1-DVI-D-1" in "/sys/class/drm/card1". With dc=1 there are "card1-DVI-D-1" and "card1-DVI-D-2".
It appears to correctly negotiate resolution and refresh rate over DDC, but because it only outputs the digital signal, a display connected over VGA receives nothing and turns off.