The Radeon driver does not work with older VGA paperwhite displays and
certain other older fixed frequency displays. The driver simply can't
detect the monitor and so it bails.
Here is the original Red Hat bug report for this issue:
I've implemented a patch to add a new config file option named "ForceLegacyCRT"
which overrides the autodetection logic and allows the user to use an older
CRT that can't be autodetected. This should be safe for single-head setups,
or multihead setups where only one monitor is connected to the Radeon
hardware, and the other head(s) are on other video cards. In a dualhead
setup using both heads on one Radeon card however, if this option is
enabled and a legacy CRT is plugged in, it is possible that one of the
monitors might be damaged due to receiving out of range signals. That isn't
a bug however, it's a limitation in the old legacy monitor.
Please apply to CVS for next release
Created attachment 482 [details] [review]
This patch applied clean to CVS when it was submitted. The Radeon driver has
subsequently been modified and the patch no longer applies. If someone looks
at this patch please, and tells me if they think it is clean enough to go in
or not, I'd appreciate it. If it is acceptable, I will port it forward so
it can be committed to CVS. If it is not, please let me know why, so I can
either clean it up to be acceptable, or drop it on the floor.
Thanks in advance.
Couldn't you force it to CRT using:
option "monitorlayout" "crt"
rather than adding a new option. you should also work on dualhead cards if you
hard code the monitor type for both crtc1 and crtc2.
This patch is no longer needed as explained in comment #3.