drm/radeon: TTM must be init with cpu-visible VRAM, v2

Without this, a bo may get created in the cpu-inaccessible vram.
Before the CP engines get setup, all copies are done via cpu memcpy.

This means that the cpu tries to read from inaccessible memory, fails,
and the radeon module proceeds to disable acceleration.

Doing this has no downsides, as the real VRAM size gets set as soon as the
CP engines get init.

This is a candidate for 3.14 fixes.

v2: Add comment on why the function is used

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

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index 77f5b0c3edb8..5cdba9b82d08 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -714,6 +714,9 @@ int radeon_ttm_init(struct radeon_device *rdev)
                 DRM_ERROR("Failed initializing VRAM heap.\n");
                 return r;
         }
+        /* Change the size here instead of the init above so only lpfn is affected */
+        radeon_ttm_set_active_vram_size(rdev, rdev->mc.visible_vram_size);
+
         r = radeon_bo_create(rdev, 256 * 1024, PAGE_SIZE, true,
                              RADEON_GEM_DOMAIN_VRAM,
                              NULL, &rdev->stollen_vga_memory);