vesa, Diamond SpeedStar, clock rates

Paul Barton-Davis (pbd@Op.Net)
Tue, 28 Jul 1998 11:38:22 -0400

The Diamond SpeedStar 24X video card comes with a little DOS utility
called 24XMODE, which can be used to set the video mode of the
card. The documentation suggests that it does little more than use
regular VESA BIOS calls to set up, for example, some graphics
mode. This, however, seems to be untrue, since using the "vga=ask"
boot parameter to accomplish the same thing fails to reset the card's
clock values. Resetting the clock values is essential to getting
reasonable resolution/refresh values under X.

I would very much like to find out what 24XMODE does, but I suspect
that its writing into the card's own memory. Right now, I run it under
dosemu, which is a pain, even though I suppose making a DEXE would
make it easier. However, using dosemu did enable me to confirm that it
doesn't do port I/O the way that you would expect for a VESA BIOS call.

Does anyone have any suggestions on how to trace what 24XMODE does ?
Does anyone already know what it does ? BTW, please, please don't
suggest that I use the DOS debugger :)


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
Please read the FAQ at