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path: root/drivers/gpu/drm/nouveau/nv50_fb.c
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Diffstat (limited to 'drivers/gpu/drm/nouveau/nv50_fb.c')
-rw-r--r--drivers/gpu/drm/nouveau/nv50_fb.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/gpu/drm/nouveau/nv50_fb.c b/drivers/gpu/drm/nouveau/nv50_fb.c
index a95e6941ba88..32611bd30e6d 100644
--- a/drivers/gpu/drm/nouveau/nv50_fb.c
+++ b/drivers/gpu/drm/nouveau/nv50_fb.c
@@ -6,10 +6,16 @@
int
nv50_fb_init(struct drm_device *dev)
{
- /* This is needed to get meaningful information from 100c90
- * on traps. No idea what these values mean exactly. */
struct drm_nouveau_private *dev_priv = dev->dev_private;
+ /* Not a clue what this is exactly. Without pointing it at a
+ * scratch page, VRAM->GART blits with M2MF (as in DDX DFS)
+ * cause IOMMU "read from address 0" errors (rh#561267)
+ */
+ nv_wr32(dev, 0x100c08, dev_priv->gart_info.sg_dummy_bus >> 8);
+
+ /* This is needed to get meaningful information from 100c90
+ * on traps. No idea what these values mean exactly. */
switch (dev_priv->chipset) {
case 0x50:
nv_wr32(dev, 0x100c90, 0x0707ff);