[Intel-gfx] [PATCH] i915: Initialize panel timing registers if VBIOS did not.

[Bryan Freed]

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 at chromium.org>
---
 drivers/gpu/drm/i915/intel_bios.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_bios.c
b/drivers/gpu/drm/i915/intel_bios.c
index ad030ff..943bbad 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -505,6 +505,15 @@ init_vbt_defaults(struct drm_i915_private *dev_priv)
  /* general features */
  dev_priv->int_tv_support = 1;
  dev_priv->int_crt_support = 1;
+
+ /* Set the Panel Power On/Off timings if uninitialized. */
+ if ((I915_READ(PP_ON_DELAYS) == 0) && (I915_READ(PP_OFF_DELAYS) == 0)) {
+ /* Set T2 to 40ms and T5 to 200ms */
+ I915_WRITE(PP_ON_DELAYS, 0x019007d0);
+
+ /* Set T3 to 35ms and Tx to 200ms */
+ I915_WRITE(PP_OFF_DELAYS, 0x015e07d0);
+ }
 }

 /**
-- 
1.7.1
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