Bug 6209

Created attachment 4883 [details]
xorg.conf

Created attachment 4884 [details]
xorg.log

Created attachment 4885 [details]
lspci

Also, forgot to mention all software (drm, Mesa, Xorg, ati) is from cvs

Change severity to enhancement. Mach64 drm is not included in the kernel.

I started looking at the mach64 drm and plan to try fixing it.

The problem was that dev->agp_buffer_token was not set, and mach64 drm would
map the DMA buffers from linear address 0x0. With the one-liner below, it
correctly maps the DMA buffers from the same linear address as the vertex bufs.

I now plan to make mach64_dma_vertex use DMA buffers.

--- mach64_dma.orig     2006-03-11 14:24:41.000000000 +0200
+++ mach64_dma.c        2006-03-11 14:25:05.000000000 +0200
@@ -834,6 +834,7 @@
                        mach64_do_cleanup_dma(dev);
                        return DRM_ERR(ENOMEM);
                }
+               dev->agp_buffer_token = init->buffers_offset;
                dev->agp_buffer_map =
                    drm_core_findmap(dev, init->buffers_offset);
                if (!dev->agp_buffer_map) {

What about the following approach:

Do not map the DMA buffers to user-space.

For dma_vertex, nothing changes.

For dma_blit, the client submits a pointer to user-space memory. 
In the AGP case nothing changes since the default method is AGP texturing (in
fact "local_textures" do not currently work with AGP, bug #6209). 
In the PCI case, the simple thing is copy_from_user to a private DMA buffer. If
the performance regression is unacceptable, we can change the blit ioctl to
submit w/h/pitch parameters and turn the memcpy currently done in user-space to
copy_from_user. I presume that its easy to determine that the pointer actually
points to memory owned by the process.

Hopefully, we can reuse the current buffer management routines. If it is
possible to do drmAddBufs without drmMapBufs, then very little changes are
required (I saw a comment in drm_mapbufs that PCI buffers are actually mapped in
drm_addbufs ...).

Sorry if I am waisting your time with uninformed assumptions,
george.

ignore the previous comment, probably bugzilla cookies ...

change title to reflect bug more precisely.

Can I commit this ?

(In reply to comment #9)
> Can I commit this ?

It seems that I don't have commit access to mesa/drm. Can I get commit access to
mesa/drm ? I have commit access to xorg (account name: gsap7).

Commited: eea150e776657faca7d5b76aca75a33dc74fbc9d