drm/i915: Set the LVDS_BORDER when using LVDS scaling mode

According to the spec the LVDS_BORDER_ENABLE bit decides whether the border
data should be included in the active display and data sent to the panel.
Border should be used when in VGA centered (un-scaled) mode or when scaling
a 4:3 source image to a wide screen panel (typical 16:9).

So when the LVDS scaling is used, decide whether the LVDS_BORDER should be
enabled or not according to the current scaling mode.

At the same time fix the typo error in LVDS center scaling mode.

https://bugs.freedesktop.org/show_bug.cgi?id=23789

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
tested-by: Zhao Jian <jian.zhao@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/i915_drv.h

@@ -492,6 +492,8 @@ typedef struct drm_i915_private {
 		struct drm_i915_gem_phys_object *phys_objs[I915_MAX_PHYS_OBJECT];
 	} mm;
 	struct sdvo_device_mapping sdvo_mappings[2];
+	/* indicate whether the LVDS_BORDER should be enabled or not */
+	unsigned int lvds_border_bits;
 
 	/* Reclocking support */
 	bool render_reclock_avail;

drivers/gpu/drm/i915/i915_reg.h

@@ -968,6 +968,8 @@
 #define   LVDS_PORT_EN			(1 << 31)
 /* Selects pipe B for LVDS data.  Must be set on pre-965. */
 #define   LVDS_PIPEB_SELECT		(1 << 30)
+/* Enable border for unscaled (or aspect-scaled) display */
+#define   LVDS_BORDER_ENABLE		(1 << 15)
 /*
  * Enables the A0-A2 data pairs and CLKA, containing 18 bits of color data per
  * pixel.

drivers/gpu/drm/i915/intel_display.c

@@ -2936,6 +2936,8 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc,
 
 		lvds = I915_READ(lvds_reg);
 		lvds |= LVDS_PORT_EN | LVDS_A0A2_CLKA_POWER_UP | LVDS_PIPEB_SELECT;
+		/* set the corresponsding LVDS_BORDER bit */
+		lvds |= dev_priv->lvds_border_bits;
 		/* Set the B0-B3 data pairs corresponding to whether we're going to
 		 * set the DPLLs for dual-channel mode or not.
 		 */

drivers/gpu/drm/i915/intel_lvds.c

@@ -380,7 +380,7 @@ static bool intel_lvds_mode_fixup(struct drm_encoder *encoder,
 				adjusted_mode->crtc_vblank_start + vsync_pos;
 		/* keep the vsync width constant */
 		adjusted_mode->crtc_vsync_end =
-				adjusted_mode->crtc_vblank_start + vsync_width;
+				adjusted_mode->crtc_vsync_start + vsync_width;
 		border = 1;
 		break;
 	case DRM_MODE_SCALE_ASPECT:
@@ -525,6 +525,14 @@ static bool intel_lvds_mode_fixup(struct drm_encoder *encoder,
 out:
 	lvds_priv->pfit_control = pfit_control;
 	lvds_priv->pfit_pgm_ratios = pfit_pgm_ratios;
+	/*
+	 * When there exists the border, it means that the LVDS_BORDR
+	 * should be enabled.
+	 */
+	if (border)
+		dev_priv->lvds_border_bits |= LVDS_BORDER_ENABLE;
+	else
+		dev_priv->lvds_border_bits &= ~(LVDS_BORDER_ENABLE);
 	/*
 	 * XXX: It would be nice to support lower refresh rates on the
 	 * panels to reduce power consumption, and perhaps match the