https://bugzilla.kernel.org/show_bug.cgi?id=200645 --- Comment #7 from Duncan (1i5t5.duncan@xxxxxxx) --- So out of curiosity I found my old DVI-D/DisplayPort adapter and tried switching outputs. First thing I noticed is that the DVI/HDMI cable I'm using is only single-link DVI, as is the DVI/DisplayPort adapter, so if I put the 4k monitor on it, it's automatically limited to 1080p. Which means that until I go buy a new cable, the only way I have to connect the 4k monitor and /get/ 4k is via the HDMI/HDMI cable and the card's HDMI connector. That leaves the DVI or DisplayPort card connector for the 1920x1080 TV. I can connect it directly to the card DVI-D using the HDMI/DVI-D cable, as I had it when I first filed this bug, or add the DVI-D/DisplayPort adaptor as well, and connect it to the card's DisplayPort, as I have it now. Either way, connecting the 1920x1080 via DVI-D or DisplayPort, the bug still manifests -- without the cap to 8bpc, trying to boot 4.18-rc1+ blanks that monitor as soon as the drmfb code takes over from the early-boot/VGA, while the HDMI-connected 4k monitor continues to work normally (at 1080p until X starts due to the video= kernel commandline option, at native 3840x2160 in X). And the problem could also be partially due to the single-link cable I'm still using for that monitor, enough for 8bpc 1920x1080, but perhaps not enough for 10bpc, even if both ends support it (I'm not actually sure whether the 1080p limited TV does or not). -- You are receiving this mail because: You are watching the assignee of the bug. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
