drm/radeon/kms: AGP systems need PCI bus mastering enabled

We might not hit this yet, but when if we do any sort of writeback
we really need to enable PCI bus mastering on these systems from
what I can see.

This enables PCI BM on all radeons that require it.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/r420.c b/drivers/gpu/drm/radeon/r420.c
index 1cefdbcc0850..e7e4f5a90ebe 100644
--- a/drivers/gpu/drm/radeon/r420.c
+++ b/drivers/gpu/drm/radeon/r420.c
@@ -335,6 +335,9 @@ int r420_init(struct radeon_device *rdev)
         if (r) {
                 return r;
         }
+        if (rdev->family == CHIP_R420)
+                r100_enable_bm(rdev);
+
         if (rdev->flags & RADEON_IS_PCIE) {
                 r = rv370_pcie_gart_init(rdev);
                 if (r)