drm/nvd9-/disp: disable display underflow reporting at init
Reported-by: Andy Ritger <aritger@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/core/engine/disp/nvd0.c b/drivers/gpu/drm/nouveau/core/engine/disp/nvd0.c
index 52dd7a1..378a015 100644
--- a/drivers/gpu/drm/nouveau/core/engine/disp/nvd0.c
+++ b/drivers/gpu/drm/nouveau/core/engine/disp/nvd0.c
@@ -541,6 +541,15 @@
nv_wr32(priv, 0x6100a0, 0x00000000);
nv_wr32(priv, 0x6100b0, 0x00000307);
+ /* disable underflow reporting, preventing an intermittent issue
+ * on some nve4 boards where the production vbios left this
+ * setting enabled by default.
+ *
+ * ftp://download.nvidia.com/open-gpu-doc/gk104-disable-underflow-reporting/1/gk104-disable-underflow-reporting.txt
+ */
+ for (i = 0; i < priv->head.nr; i++)
+ nv_mask(priv, 0x616308 + (i * 0x800), 0x00000111, 0x00000010);
+
return 0;
}