Tim Roberts wrote:
Andrew C Aitchison wrote:
There are two cases where XFree86 does need kernel support.This doesn't actually REQUIRE agpgart support from the kernel unless
* Chipsets like the i810/i815/i835/... family have no framebuffer memory
but use main system memory for the framebuffer. This requires agpgart
support from the kernel.
you're doing bus mastering. The ProSavages are UMA chips, with their
frame buffers in main memory, and as long as the BIOS has done the
proper division of memory at boot time, that's all it needs.
Many of the cards in the i810 family have only a very limited
amount of video memory on the card. So if you want to get anything over
800x600 on them, you need agpgart. On some of them the i810
driver won't start even in 800x600 mode, so VESA is the only option.
I was about to express my utter confusion at these comments, since in fact the i810 family (just like the ProSavages and other UMA solutions) has exactly zero megabytes on-chip video memory, but after doing some reading, I think I understand now.
The issue here, if I understand it, is that the BIOS on i810 systems is utterly brain-dead. It will not allocate more than 1 MB of system RAM to the i810. Thus, if you want more than 1024x768x8 or 800x600x16, you do, in fact, need agpgart support to remap the addresses.
This is NOT the case for ProSavage chips, nor for any of the other UMA chips I've encountered (like SiS). In those cases, the BIOS carves up the system memory, and is able to allocate 8MB or 16MB or more to the graphics chip. In that case, agpgart is not necessary.
So, I guess I learned something today.
-- - Tim Roberts, [EMAIL PROTECTED] Providenza & Boekelheide, Inc.
_______________________________________________ Devel mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/devel
