https://bugs.freedesktop.org/show_bug.cgi?id=107414
--- Comment #1 from Timothy Pearson tpearson@raptorengineering.com --- I'm also seeing this on 4.20 with amdgpu. In my case though it also triggers a problem with amdgpu, a problem that would not be hit if the options were honored correctly:
[ 7.843957] [drm] Display Core initialized with v3.1.68! [ 7.844448] [drm] forcing DP-3 connector on [ 11.785325] [drm:emulated_link_detect [amdgpu]] *ERROR* Failed to read EDID [ 11.785372] [drm] forcing DP-4 connector on [ 11.805994] [drm] Got external EDID base block and 1 extension from "edid/edid.bin" for connector "DP-4" [ 11.822809] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). [ 11.822825] [drm] Driver supports precise vblank timestamp query. [ 11.849368] [drm] UVD and UVD ENC initialized successfully. [ 11.950326] [drm] VCE initialized successfully. [ 11.950636] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* No EDID firmware found on connector: DP-3 ,forcing to OFF! [ 11.950731] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* No EDID firmware found on connector: DP-3 ,forcing to OFF! [ 11.950782] ------------[ cut here ]------------ [ 11.950802] kernel BUG at mm/slub.c:294
Kernel command line: amdgpu.dc=1 drm_kms_helper.edid_firmware=DP-3:edid/edid.bin drm_kms_helper.edid_firmware=DP-4:edid/edid.bin video=DP-3:1920x1080D video=DP-4:1920x1080D
This is for a video broadcast system that "features" output sinks being connected and disconnected quite frequently; this should be handled seamlessly but Linux is not honoring the options here.