drm/radeon/kms: set gart pages to invalid on unbind and point to dummy page

this uses a new entrypoint to invalidate gart entries instead of using 0.
Changed to rather than pointing to 0 address point empty entry to dummy
page. This might help to avoid hard lockup if for some wrong
reasons GPU try to access unmapped GART entry.

I'm not 100% sure this is going to work, we probably need to allocate
a dummy page and point all the GTT entries at it similiar to what AGP does.
but we can test this first I suppose.

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

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/rv770.c b/drivers/gpu/drm/radeon/rv770.c
index 3ecd138815d8..6f1f4abbe88c 100644
--- a/drivers/gpu/drm/radeon/rv770.c
+++ b/drivers/gpu/drm/radeon/rv770.c
@@ -56,6 +56,7 @@ int rv770_pcie_gart_enable(struct radeon_device *rdev)
         r = radeon_gart_table_vram_pin(rdev);
         if (r)
                 return r;
+        radeon_gart_restore(rdev);
         /* Setup L2 cache */
         WREG32(VM_L2_CNTL, ENABLE_L2_CACHE | ENABLE_L2_FRAGMENT_PROCESSING |
                                 ENABLE_L2_PTE_CACHE_LRU_UPDATE_BY_WRITE |