From 4eb3033c72099fab3536ed8ac54a5dc99f0832d7 Mon Sep 17 00:00:00 2001 From: Ben Skeggs Date: Mon, 7 Jun 2010 13:59:40 +1000 Subject: drm/nv50: fix iommu errors caused by device reading from address 0 Signed-off-by: Ben Skeggs Signed-off-by: Dave Airlie --- drivers/gpu/drm/nouveau/nv50_fb.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'drivers/gpu') diff --git a/drivers/gpu/drm/nouveau/nv50_fb.c b/drivers/gpu/drm/nouveau/nv50_fb.c index a95e6941ba8..32611bd30e6 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); -- cgit v1.2.3-70-g09d2