From 0e9a6694305d6e8a9afd0e0f67e9fa430f4a913d Mon Sep 17 00:00:00 2001
From: Jesse Barnes <jbarnes@virtuousgeek.org>
Date: Thu, 12 Jan 2012 14:51:17 -0800
Subject: [PATCH 01/69] drm/i915: mask transcoder select bits before setting
 them on LVDS

commit 7885d2052bd94395e337709cfba093a41f273ff1 upstream.

The transcoder port may changed from mode set to mode set, so make sure
to mask out the selection bits before setting the right ones or we'll
get black screens when going from transcoder B to A.

Tested-by: Vincent Vanackere <vincent.vanackere@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
Cc: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/i915/intel_display.c |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 9011f48..390768f 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5646,12 +5646,15 @@ static int ironlake_crtc_mode_set(struct drm_crtc *crtc,
 	if (is_lvds) {
 		temp = I915_READ(PCH_LVDS);
 		temp |= LVDS_PORT_EN | LVDS_A0A2_CLKA_POWER_UP;
-		if (HAS_PCH_CPT(dev))
+		if (HAS_PCH_CPT(dev)) {
+			temp &= ~PORT_TRANS_SEL_MASK;
 			temp |= PORT_TRANS_SEL_CPT(pipe);
-		else if (pipe == 1)
-			temp |= LVDS_PIPEB_SELECT;
-		else
-			temp &= ~LVDS_PIPEB_SELECT;
+		} else {
+			if (pipe == 1)
+				temp |= LVDS_PIPEB_SELECT;
+			else
+				temp &= ~LVDS_PIPEB_SELECT;
+		}
 
 		/* set the corresponsding LVDS_BORDER bit */
 		temp |= dev_priv->lvds_border_bits;
-- 
1.7.9.5

