I have seen several posts about unreadable desktops when ATI fglrx drivers connect to large screen displays, such as HDTVs.
I have found that the following solution works for me; it may not be the “best” way, please comment if you have a better work around.
When the fglrx driver is installed and an initial configuration established with
aticonfig --initial
several entries are made in /etc/X11/xorg.conf, including this:
Section "Monitor"
Identifier "aticonfig-Monitor[0]-0"
Option "VendorName" "ATI Proprietary Driver"
Option "ModelName" "Generic Autodetecting Monitor"
Option "DPMS" "true"
EndSection
It seems by default that the connected monitor characteristics are re-read each time X starts up and a configuration is dynamically set up. With very large displays (e.g. my 1600 mm x 900mm DLP), this yields a calculated DPI around 20,20 or so and the fonts are unreadible on the display. When running cloned mode with a “normal” monitor, this usually affects both displays; it becomes impossible to read anything that is font based.
My solution is to modify xorg.conf to read
Section "Monitor"
Identifier "aticonfig-Monitor[0]-0"
#added to force reasonable sized fonts
DisplaySize 400 225
#
Option "VendorName" "ATI Proprietary Driver"
Option "ModelName" "Generic Autodetecting Monitor"
Option "DPMS" "true"
EndSection
This overrides what EDID reports to X on startup.
You can see the result in /var/log/Xorg.0.log
.....
......
(WW) fglrx(0): Probed monitor is 1600x900 mm, using Displaysize 400x225 mm
(**) fglrx(0): DPI set to (121, 121)
(--) fglrx(0): Virtual size is 1920x1080 (pitch 1920)
.....
.....
There may be unexpected side effects, but I have not hit them as yet.
If the is a more correct way to do this, please comment.