drm/i915: Initialize panel timing registers if VBIOS did not

The time between start of the pixel clock and backlight enable is a basic
panel timing constraint.  If the Panel Power On/Off registers are found
to be 0, assume we are booting without VBIOS initialization and set these
registers to something reasonable.

Change-Id: Ibed6cc10d46bf52fd92e0beb25ae3525b5eef99d
Signed-off-by: Bryan Freed <bfreed@chromium.org>
[ickle: rearranged into a separate function to distinguish its role from
simply parsing the VBIOS tables.]
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 2caf43d..35d121c 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1235,7 +1235,7 @@
 	 */
 	dev_priv->allow_batchbuffer = 1;
 
-	ret = intel_init_bios(dev);
+	ret = intel_parse_bios(dev);
 	if (ret)
 		DRM_INFO("failed to find VBIOS tables\n");
 
@@ -2001,6 +2001,9 @@
 	intel_setup_gmbus(dev);
 	intel_opregion_setup(dev);
 
+	/* Make sure the bios did its job and set up vital registers */
+	intel_setup_bios(dev);
+
 	i915_gem_load(dev);
 
 	/* Init HWS */