https://bugs.freedesktop.org/show_bug.cgi?id=66963
--- Comment #104 from Eugene ken20001@ukr.net --- (In reply to comment #103)
(In reply to comment #102)
If you could explain me where is kernel command line (when I'm seeing GRUB menu push "e" or "c"; and if "c" what to do after I entered radeon.modeset=0 in there?), I would try it. I'm just a newbie using kubuntu a few months.
in the grub menu select the kernel you want to boot and press 'e' then move to the end of the line that starts: linux /boot/<blah blah blah> and append the options to the end of that line. e.g., linux /boot/<blah blah blah> radeon.modeset=0 1 The '1' means boot into single user mode rather than X.
Also, if you haven't already, try disabling aspm: linux /boot/<blah blah blah> radeon.aspm=0 radeon.dpm=1
Thanks for your explanations. Recently tried it. But...:
with
linux /boot/<blah blah blah> radeon.aspm=0 radeon.dpm=1
still blank screen after starting kernel loading
with
linux /boot/<blah blah blah> radeon.modeset=0 1
it seems it's booting but I can't see command line - only black screen or text line: "kernel booting... bla-bla-bla" and also no command line. Trying to enter anything gives nothing. But if a enter "reboot" and press Enter it restarts. So it gets the commands but I can't see any display output.