[rfc] Radeon AGP support patches

[Tijl Coosemans]

On Mon, 27 Oct 2014 18:27:53 +0200 Konstantin Belousov <kostikbel at gmail.com> wrote:
> On Mon, Oct 27, 2014 at 05:00:55PM +0100, Tijl Coosemans wrote:
>> In ttm_agp_bind the ttm->pages array is already populated.  These are
>> the pages that need to be put into the GTT.  The patch modifies struct
>> agp_memory in sys/dev/agp such that ttm->pages can be passed via
>> agp_bind_memory.  Maybe it would be better to add two new functions to
>> sys/dev/agp/agp.c: agp_bind_pages and agp_unbind_pages.  These would
>> take a vm_page_t array as argument and bind/unbind the pages directly
>> in the GTT.  There's no need for ttm_agp_bind to call agp_alloc_memory
>> then and struct agp_memory would not be involved at all.  Does that
>> sound better?
> 
> Yes, this approach is much better IMO.  Having discriminated storage
> for the bound pages is too ugly;

New patch 1 & 3 attached.

> was the whole code audited for correctness after the change ?

I'm fairly confident these patches are all that's needed yes.  I made
a first implementation on Sunday afternoon.  It got to the point that
X showed a mouse pointer and background colour and then it crashed.
It took the rest of the week to figure out why (NULL dereference in
ttm_bo_vm_fault) and how to solve it (mark aperture range fictitious).
It's hard to debug something without a screen.  I read the code front
to back and back to front in that time and compared it with the old DRM
code and with the Linux DRM code.  That's where patch 2 & 4 come from.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: radeon-agp-1.patch
Type: text/x-patch
Size: 2793 bytes
Desc: not available
URL: <http://lists.freebsd.org/pipermail/freebsd-x11/attachments/20141027/805fee7a/attachment.bin>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: radeon-agp-3.patch
Type: text/x-patch
Size: 9308 bytes
Desc: not available
URL: <http://lists.freebsd.org/pipermail/freebsd-x11/attachments/20141027/805fee7a/attachment-0001.bin>