CRT/LCD Switching under X

[Pedro "I." Sanchez <pedro.i.sanchez@altavista.net>]

Hi,

I'm running debian/testing on my Dell Latitude (C family) with X 4.0.3.
The video adapter is supported through the "ATI" driver and it is
recognized as a MACH64 device.

While on an X session, and if connected to an external monitor, I can
switch the video output to either the flat panel (LCD) OR to the
external monitor by pressing Fn-F7 (this is the CRT/LCD switch function)
but not to both devices simultaneously.This quite annoying to me when
doing presentations.

I dual boot this laptop with Window NT. When running NT, Fn-F7 cycles
the video output as LCD--CRT--LCD/CRT--LCD--CRT--LCD/CRT..., so I know
the laptop can drive both video outputs simultaneously. Also, I just
noticed that selecting "Full Screen" mode in VMware while running in CRT
mode switches the display to both LCD and CRT simultaneously!

So to summarize, I only get the combo LCD/CRT if I run windows NT either
natively or through VMware. Outside these two environments it is just
one or the other.

Do you have any ideas about what to change, I guess in the X config
file, to get to the video modes to work simultaneously under standard
Linux?

Thank you,

-- 
Pedro