Just to say that I experienced this problem with my Radeon 7500 DVI/CRT
dual head card. I rebooted my box last weekend after 115 days uptime -
during which X was upgraded. After reboot, instead of producing a
separate display on each monitor, the same display was duplicated on
both. I had made no other changes to the configuration files for X in
the meantime.
Adding the 'Option "MonitorLayout" "CRT,CRT"' string to both device
sections as suggested worked, however, and I now have normal
functionality restored.
Thanks,
Tony Whitmore