Your dmesg says ... vga1 at pci1 dev 0 function 0 "ATI Radeon HD 8600" rev 0x00 ...
but I don't see this listed in "man 4 radeon". https://man.openbsd.org/radeon Cannot say for sure but it may not be supported. Have a look at the log for X. Might provide info. Good luck <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Virus-free. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
