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

[Alex Deucher]

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>
Cc: stable at kernel.org
---
 drivers/gpu/drm/radeon/evergreen.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c
index 2117cf5..f8c0f15 100644
--- a/drivers/gpu/drm/radeon/evergreen.c
+++ b/drivers/gpu/drm/radeon/evergreen.c
@@ -1480,6 +1480,8 @@ int evergreen_mc_init(struct radeon_device *rdev)
 	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);
 
-- 
1.7.1.1