drm/nouveau: Disable PROM access on init.

On older cards (<nv17) scanout gets blocked when the ROM is being
accessed. PROM access usually comes out enabled from suspend, switch
it off.

Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/gpu/drm/nouveau/nv04_mc.c b/drivers/gpu/drm/nouveau/nv04_mc.c
index 617ed1e05269..2af43a1cb2ec 100644
--- a/drivers/gpu/drm/nouveau/nv04_mc.c
+++ b/drivers/gpu/drm/nouveau/nv04_mc.c
@@ -11,6 +11,10 @@ nv04_mc_init(struct drm_device *dev)
          */
 
         nv_wr32(dev, NV03_PMC_ENABLE, 0xFFFFFFFF);
+
+        /* Disable PROM access. */
+        nv_wr32(dev, NV_PBUS_PCI_NV_20, NV_PBUS_PCI_NV_20_ROM_SHADOW_ENABLED);
+
         return 0;
 }