agp_i810 not built on amd64?

Nate Lawson nate at
Fri May 4 22:04:12 UTC 2007

Eric Anholt wrote:
> On Fri, 2007-05-04 at 13:13 -0700, Nate Lawson wrote:
>> I have a desktop with i945GMS builtin video.  It appears agp_i810.c is
>> not built on amd64, hence no support for agp.  This is on 6.x.
>> none0 at pci0:2:0: class=0x030000 card=0x31031565 chip=0x27728086 rev=0x02
>> hdr=0x00
>>     vendor     = 'Intel Corporation'
>>     device     = 'Integrated Graphics Controller'
>>     class      = display
>>     subclass   = VGA
>> sys/conf/files.i386:pci/agp_i810.c                     optional agp
>> $ ls /sys/amd64/compile/SMP/*agp*
>> /sys/amd64/compile/SMP/agp.o            /sys/amd64/compile/SMP/agp_if.h
>> /sys/amd64/compile/SMP/agp_amd64.o      /sys/amd64/compile/SMP/agp_if.o
>> /sys/amd64/compile/SMP/agp_if.c         /sys/amd64/compile/SMP/agp_intel.o
>> Is there any reason not to use i810 on amd64?  A quick glance through
>> doesn't show it doing anything 32-bit specific.  On -current, it appears
>> to be enabled for amd64.  It appears this MFC never happened:
>> revision 1.93
>> date: 2006/09/05 16:55:12;  author: anholt;  state: Exp;  lines: +1 -0
>> Include agp_i810.c in amd64 AGP builds to get support for the Intel 915
>> Express chipsets.
> Nope, there's no good reason for the MFC to have not happened.
> We've only got one amd64 issue that I know of, but it's actually not
> unique to amd64.  We're not allocating our pages to back aperture
> allocations to meet the requirements of the page tables, so for example
> on i915-class hardware with 4GB of ram, you'll get pages sometimes that
> are above the 4GB range, and we'll just drop the top bit of the address
> when filling in the page table, resulting in pain.  We need a way for
> AGP drivers to communicate their requirements for AGP memory to the
> core, likely through busdma tags.
> In the current agp_i810.c patch I've been working on, I at least panic
> when we get out-of-range pages, instead of scribbling on random memory.

Ok, I've tested it and it works.  I will MFC now.


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