[Intel-gfx] [PATCH] drm/i915: check that the i965g/gm 4G limit is really obeyed

[Daniel Vetter]

In truly crazy circumstances shmem might give us the wrong type of
page. So be a bit paranoid and double check this.

Cc: Rob Clark <robdclark at gmail.com>
References: http://lkml.org/lkml/2011/7/11/238
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_gem.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 8508b3d..55fdd20 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1827,6 +1827,9 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
 			sg->length += PAGE_SIZE;
 		}
 		last_pfn = page_to_pfn(page);
+
+		/* Check that the i965g/gm workaround works. */
+		WARN_ON((gfp & __GFP_DMA32) && (last_pfn >= 0x00100000UL));
 	}
 #ifdef CONFIG_SWIOTLB
 	if (!swiotlb_nr_tbl())
-- 
1.8.3.2