[rfc] Radeon AGP support patches

[Tijl Coosemans]

On Sun, 26 Oct 2014 16:24:42 +0100 Tijl Coosemans <tijl at FreeBSD.org> wrote:
> I worked on AGP support for Radeon cards this week.

Results from the small benchmark test built into the driver:

RV350 in PCI mode:
dma 1024 bo moves of 1024 kB from 2 to 4 in 13419 ms, throughput: 624 Mb/s or 78 MB/s
blit 1024 bo moves of 1024 kB from 2 to 4 in 22959 ms, throughput: 360 Mb/s or 45 MB/s
dma 1024 bo moves of 1024 kB from 4 to 2 in 4289 ms, throughput: 1952 Mb/s or 244 MB/s
blit 1024 bo moves of 1024 kB from 4 to 2 in 8020 ms, throughput: 1040 Mb/s or 130 MB/s

RV350 in AGP mode:
dma 1024 bo moves of 1024 kB from 2 to 4 in 3100 ms, throughput: 2704 Mb/s or 338 MB/s
blit 1024 bo moves of 1024 kB from 2 to 4 in 1236 ms, throughput: 6784 Mb/s or 848 MB/s
dma 1024 bo moves of 1024 kB from 4 to 2 in 2535 ms, throughput: 3304 Mb/s or 413 MB/s
blit 1024 bo moves of 1024 kB from 4 to 2 in 2537 ms, throughput: 3304 Mb/s or 413 MB/s