drm/radeon: disable AGP by default

[ Upstream commit ba806f98 ]

Always use the PCI GART instead. We just have to many cases
where AGP still causes problems. This means a performance
regression for some GPUs, but also a bug fix for some others.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/gpu/drm/radeon/radeon_drv.c

@@ -168,12 +168,7 @@ int radeon_no_wb;
 int radeon_modeset = -1;
 int radeon_dynclks = -1;
 int radeon_r4xx_atom = 0;
-#ifdef __powerpc__
-/* Default to PCI on PowerPC (fdo #95017) */
 int radeon_agpmode = -1;
-#else
-int radeon_agpmode = 0;
-#endif
 int radeon_vram_limit = 0;
 int radeon_gart_size = -1; /* auto */
 int radeon_benchmarking = 0;