xf86-video-chips driver support for multiple heads & CPU to Screen Color Expansion

[Donald Kayser]

Hello,

I have been able to modify the driver to support independent images on  
each head for the C&T 69030. I will make it available to all when  
complete. I do not intend to check this in for a few reasons. 1) I  
didn't like the way it was written with respect to formatting and with  
respect to the number of devices it supports. 2) I only needed to  
support one device, so I have mostly stripped out any code that did  
not compile for my platform. Trying to cram and learn enough of  
xserver and driver code into one several week project was enough of a  
task. 3) These changes only work on the X7.3 release. I don't need it  
to work beyond that, even for the target I have. 4) The code only  
supported mirrored data from one head to the other, it also used IO  
space that get's mapped to PCI/IO space to communicate with the driver  
and partly uses memory registers. My product has two 69030  
controllers, so only memory mapped I/O is allowed. 5) I made major  
changes to the way registers are restored, and have no way of testing  
against any other platforms.

Now, I have problems with CPU to Screen Color Expansion. When the XAA  
architecture uses color expansion registers to transfer data to the  
graphics memory, it is not accomplished through the frame buffer, but  
through a 64K bit of PCI bus memory. I have a PPC processor, so I have  
to worry about byte swapping, and all data that is Blit'd out he 64K  
addresses have an odd swapping going on. It is hard to describe, but  
if you start xfontsel and pick a family of nice 8x8 fixed pitch font  
and look at the display, it read BADCFE... This has to be a swapping  
problem somewhere, so I was wondering if anyone had insight on the  
color expansion notion in a PPC environment.

Thanks,
Donald
xorg at kayser.net