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

[Alex Deucher]

On Tue, Jun 23, 2009 at 12:14 PM, Donald Kayser<xorg at kayser.net> wrote:
> 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.

Could you post the patch to the mailing list or file a bug with the
patch so it will be available to future developers?

Alex