[067/103] drm/radeon/kms: fix possible sigbus in evergreen accel code

[Greg KH]

2.6.35-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Alex Deucher <alexdeucher at gmail.com>

Not upstream in Linus's tree as it was fixed by a much more intrusive
patch in a different manner, commit c919b371cb734f42b11


2.6.35 and 2.6.36 do not contain blit support for evergreen
asics so if they use unmappable vram, you can end up with an
unreachable buffer address.  This should not be applied to drm-next
as that tree already contains evergreen blit support.  This should
only be applied to the 2.6.35 and 2.6.36 stable trees.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=30188

Signed-off-by: Alex Deucher <alexdeucher at gmail.com>
Acked-by: Dave Airlie <airlied at redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at suse.de>

---
 drivers/gpu/drm/radeon/evergreen.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/gpu/drm/radeon/evergreen.c
+++ b/drivers/gpu/drm/radeon/evergreen.c
@@ -1389,6 +1389,8 @@ int evergreen_mc_init(struct radeon_devi
 	rdev->mc.mc_vram_size = RREG32(CONFIG_MEMSIZE) * 1024 * 1024;
 	rdev->mc.real_vram_size = RREG32(CONFIG_MEMSIZE) * 1024 * 1024;
 	rdev->mc.visible_vram_size = rdev->mc.aper_size;
+	/* limit it to the aperture size for now as there is no blit support in 2.6.35/36*/
+	rdev->mc.real_vram_size = rdev->mc.visible_vram_size;
 	r600_vram_gtt_location(rdev, &rdev->mc);
 	radeon_update_bandwidth_info(rdev);