i915/gtt: fix ordering causing DMAR errors on object teardown.

Previous to the last GTT rework we always rewrote the GTT then unmapped the
object, somehow this got reversed in the rework in 2.6.37-rc5 timeframe.

This fix needs to go to stable in an alternate form since the code changed.

This fixes DMAR reports on my Ironlake HP2540p.

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

diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
index b7c0c7ee67c87f5fc5d4ed6f51f4c44735fa5175..e921b693412b9ec4dc994340c3724ee99dcc94b4 100644 (file)
--- a/drivers/char/agp/intel-gtt.c
+++ b/drivers/char/agp/intel-gtt.c
@@ -1000,14 +1000,14 @@ static int intel_fake_agp_remove_entries(struct agp_memory *mem,
        if (mem->page_count == 0)
                return 0;
 
+       intel_gtt_clear_range(pg_start, mem->page_count);
+
        if (intel_private.base.needs_dmar) {
                intel_gtt_unmap_memory(mem->sg_list, mem->num_sg);
                mem->sg_list = NULL;
                mem->num_sg = 0;
        }
 
-       intel_gtt_clear_range(pg_start, mem->page_count);
-
        return 0;
 }