commit b71dd2dd5b28fe7ca69175e5d49f9bbc627021fc
Author: Florian Mickler <florian@mickler.org>
Date:   Tue Jul 7 12:22:28 2009 +0200

    debug the channel_bits part
    this gives:
    [    0.425863] [dmk:parse_lfp_panel_data], LVDS_OPTIONS SETTINGS:
    [    0.425865] [dmk:parse_lfp_panel_data], panel_type: 2
    [    0.425867] [dmk:parse_lfp_panel_data], channel_bits 0
    [    0.425869] [dmk:parse_lfp_panel_data], mask: 12
    [    0.425871] [dmk:parse_lfp_panel_data], the_channel_bits: 0
    [    0.425873] [dmk:parse_lfp_panel_data], the backshifted bits: 0
    
    what do you think about the find_best_PLL part?

diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index ae3a58c..98430bf 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -115,12 +115,18 @@ parse_lfp_panel_data(struct drm_i915_private *dev_priv,
 	lvds_options = find_section(bdb, BDB_LVDS_OPTIONS);
 	if (!lvds_options)
 		return;
-
+	DRM_DEBUG_KMS("dmk","LVDS_OPTIONS SETTINGS:\n");
+	DRM_DEBUG_KMS("dmk","panel_type: %d \n",lvds_options->panel_type);
+	DRM_DEBUG_KMS("dmk","channel_bits %d \n",lvds_options->lvds_channel_bits);
+	DRM_DEBUG_KMS("dmk","mask: %d \n",3<<lvds_options->panel_type);
 	/* Fetch lvds channel info */
 	channel_bits = lvds_options->lvds_channel_bits &
 		       (3 << lvds_options->panel_type);
+	DRM_DEBUG_KMS("dmk","the_channel_bits: %d \n",channel_bits);
+	DRM_DEBUG_KMS("dmk","the backshifted bits: %d \n",channel_bits >> lvds_options->panel_type);
 	if (channel_bits) {
 		channel_bits = channel_bits >> lvds_options->panel_type;
+		/* LVDS_DUAL_CHANNEL is 000...0010 (0x2) */
 		if (channel_bits == LVDS_DUAL_CHANNEL)
 			dev_priv->lvds_dual_channel = 1;
 	}
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 4699097..0391e6f 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -642,20 +642,24 @@ intel_find_best_PLL(const intel_limit_t *limit, struct drm_crtc *crtc,
 	intel_clock_t clock;
 	int err = target;
 
-	if (IS_I9XX(dev) && intel_pipe_has_type(crtc, INTEL_OUTPUT_LVDS) &&
-	    ((I915_READ(LVDS) & LVDS_PORT_EN) != 0 ||
-	     dev_priv->lvds_dual_channel)) {
+	if (IS_I9XX(dev) && intel_pipe_has_type(crtc, INTEL_OUTPUT_LVDS)){
 		/*
 		 * For LVDS, if the panel is on, just rely on its current
-		 * settings for dual-channel.  We haven't figured out how to
-		 * reliably set up different single/dual channel state, if we
-		 * even can.
+		 * settings for dual-channel.  
+		 * Else we rely on the bios panel properties.
 		 */
-		if ((I915_READ(LVDS) & LVDS_CLKB_POWER_MASK) ==
-		    LVDS_CLKB_POWER_UP)
-			clock.p2 = limit->p2.p2_fast;
-		else
-			clock.p2 = limit->p2.p2_slow;
+		if (I915_READ(LVDS) & LVDS_PORT_EN)  {
+			if ((I915_READ(LVDS) & LVDS_CLKB_POWER_MASK) ==
+			    LVDS_CLKB_POWER_UP) 
+				clock.p2 = limit->p2.p2_fast;
+			else
+				clock.p2 = limit->p2.p2_slow;
+		} else {
+		 	if  ( dev_priv->lvds_dual_channel ) 
+				clock.p2 = limit->p2.p2_fast;
+			else
+				clock.p2 = limit->p2.p2_slow;
+		}
 	} else {
 		if (target < limit->p2.dot_limit)
 			clock.p2 = limit->p2.p2_slow;