drm: tegra: fix front_porch <-> back_porch mixup

Fixes wrong picture offset observed when using HDMI output with a
Technisat HD TV.
Signed-off-by: Lucas Stach <dev@lynxeye.de>
Acked-by: Mark Zhang <markz@nvidia.com>
Tested-by: Mark Zhang <markz@nvidia.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/tegra/dc.c

@@ -102,12 +102,12 @@ static int tegra_dc_set_timings(struct tegra_dc *dc,
 		((mode->hsync_end - mode->hsync_start) <<  0);
 	tegra_dc_writel(dc, value, DC_DISP_SYNC_WIDTH);
 
-	value = ((mode->vsync_start - mode->vdisplay) << 16) |
-		((mode->hsync_start - mode->hdisplay) <<  0);
-	tegra_dc_writel(dc, value, DC_DISP_BACK_PORCH);
-
 	value = ((mode->vtotal - mode->vsync_end) << 16) |
 		((mode->htotal - mode->hsync_end) <<  0);
+	tegra_dc_writel(dc, value, DC_DISP_BACK_PORCH);
+
+	value = ((mode->vsync_start - mode->vdisplay) << 16) |
+		((mode->hsync_start - mode->hdisplay) <<  0);
 	tegra_dc_writel(dc, value, DC_DISP_FRONT_PORCH);
 
 	value = (mode->vdisplay << 16) | mode->hdisplay;

drivers/gpu/drm/tegra/hdmi.c

@@ -479,7 +479,7 @@ static void tegra_hdmi_setup_avi_infoframe(struct tegra_hdmi *hdmi,
 		return;
 	}
 
-	h_front_porch = mode->htotal - mode->hsync_end;
+	h_front_porch = mode->hsync_start - mode->hdisplay;
 	memset(&frame, 0, sizeof(frame));
 	frame.r = HDMI_AVI_R_SAME;
 
@@ -634,8 +634,8 @@ static int tegra_output_hdmi_enable(struct tegra_output *output)
 
 	pclk = mode->clock * 1000;
 	h_sync_width = mode->hsync_end - mode->hsync_start;
-	h_front_porch = mode->htotal - mode->hsync_end;
-	h_back_porch = mode->hsync_start - mode->hdisplay;
+	h_back_porch = mode->htotal - mode->hsync_end;
+	h_front_porch = mode->hsync_start - mode->hdisplay;
 
 	err = regulator_enable(hdmi->vdd);
 	if (err < 0) {