drm/radeon: stop poisoning the GART TLB

When we set the valid bit on invalid GART entries they are
loaded into the TLB when an adjacent entry is loaded. This
poisons the TLB with invalid entries which are sometimes
not correctly removed on TLB flush.

For stable inclusion the patch probably needs to be modified a bit.

Signed-off-by: Christian König <christian.koenig@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/radeon/rs600.c b/drivers/gpu/drm/radeon/rs600.c
index 0a8be63926d8dd9e078127ae4581a05cb1a584fa..e0465b2cde399a0345ac5a4baf539c1d70884afa 100644 (file)
--- a/drivers/gpu/drm/radeon/rs600.c
+++ b/drivers/gpu/drm/radeon/rs600.c
@@ -634,7 +634,10 @@ int rs600_gart_set_page(struct radeon_device *rdev, int i, uint64_t addr)
                return -EINVAL;
        }
        addr = addr & 0xFFFFFFFFFFFFF000ULL;
-       addr |= R600_PTE_GART;
+       if (addr == rdev->dummy_page.addr)
+               addr |= R600_PTE_SYSTEM | R600_PTE_SNOOPED;
+       else
+               addr |= R600_PTE_GART;
        writeq(addr, ptr + (i * 8));
        return 0;
 }