drm/i915: Fix LVDS panel fitting on Arrandale

Arrandale has new window based method for panel fitting.
This one enables full screen aspect scaling on LVDS. It fixes
standard mode display failure on LVDS for Arrandale.

Cc: Stable Team <stable@kernel.org>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

drivers/gpu/drm/i915/intel_display.c

@@ -1391,6 +1391,7 @@ static void igdng_crtc_dpms(struct drm_crtc *crtc, int mode)
 	int transconf_reg = (pipe == 0) ? TRANSACONF : TRANSBCONF;
 	int pf_ctl_reg = (pipe == 0) ? PFA_CTL_1 : PFB_CTL_1;
 	int pf_win_size = (pipe == 0) ? PFA_WIN_SZ : PFB_WIN_SZ;
+	int pf_win_pos = (pipe == 0) ? PFA_WIN_POS : PFB_WIN_POS;
 	int cpu_htot_reg = (pipe == 0) ? HTOTAL_A : HTOTAL_B;
 	int cpu_hblank_reg = (pipe == 0) ? HBLANK_A : HBLANK_B;
 	int cpu_hsync_reg = (pipe == 0) ? HSYNC_A : HSYNC_B;
@@ -1442,6 +1443,19 @@ static void igdng_crtc_dpms(struct drm_crtc *crtc, int mode)
 			}
 		}
 
+		/* Enable panel fitting for LVDS */
+		if (intel_pipe_has_type(crtc, INTEL_OUTPUT_LVDS)) {
+			temp = I915_READ(pf_ctl_reg);
+			I915_WRITE(pf_ctl_reg, temp | PF_ENABLE);
+
+			/* currently full aspect */
+			I915_WRITE(pf_win_pos, 0);
+
+			I915_WRITE(pf_win_size,
+				   (dev_priv->panel_fixed_mode->hdisplay << 16) |
+				   (dev_priv->panel_fixed_mode->vdisplay));
+		}
+
 		/* Enable CPU pipe */
 		temp = I915_READ(pipeconf_reg);
 		if ((temp & PIPEACONF_ENABLE) == 0) {