I'm a relatively recent subscriber to this mailing list and by accident discovered that a framebuffer device for the i810 was already being developed. In the meantime, I was also trying to brew a device of my own and it's already functional by the time I happen to find out.
Anyways, the device I have made should work in 640-1600 horizontal resolution at 2,4,8 and 16 bpp with unaccelerated and accelerated functions (excluding clear_margins), and mtrr. These options are selectable at kernel boot time. At present, the device will compile with kernel 2.2.19 (I have a very slow modem and still thinking of downloading kernel 2.4.x). To make it work with X, I forego using the kernel agpgart and have the device handle it's own agp allocation routines. However, since there is really no interface between X/agpgart and the framebuffer, switching to and from X and the fb console is still a bit tricky and nearly an ugly hack, but is doable and works almost all of the time (at least in my test box). There are still a few bugs, the most major of which is that X, although will work in its native mode, will NOT work when using fbdev :( (still trying to work on this). There are also initial screen corruptions during transition from standard vga mode to hig!
resolution mode, and a few others.
I'll probably stop developing this driver (it's a waste of effort) and I would like to contribute patches to the developers of the i810 fb module if the developers will not mind. Who should I send it too?
For anyone interested in this driver, please let me know and I'll send a kernel patch/file via e-mail. Sorry, I don't have any access to an ftp or http site.