4 files changed, 45 insertions, 8 deletions

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index 386f3b4b009..9336006b475 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -1100,8 +1100,6 @@ static int tegra_dc_init(struct host1x_client *client)
 	struct tegra_dc *dc = host1x_client_to_dc(client);
 	int err;
 
-	dc->pipe = tegra->drm->mode_config.num_crtc;
-
 	drm_crtc_init(tegra->drm, &dc->base, &tegra_crtc_funcs);
 	drm_mode_crtc_set_gamma_size(&dc->base, 256);
 	drm_crtc_helper_add(&dc->base, &tegra_crtc_helper_funcs);
@@ -1187,6 +1185,41 @@ static const struct of_device_id tegra_dc_of_match[] = {
 	}
 };
 
+static int tegra_dc_parse_dt(struct tegra_dc *dc)
+{
+	struct device_node *np;
+	u32 value = 0;
+	int err;
+
+	err = of_property_read_u32(dc->dev->of_node, "nvidia,head", &value);
+	if (err < 0) {
+		dev_err(dc->dev, "missing \"nvidia,head\" property\n");
+
+		/*
+		 * If the nvidia,head property isn't present, try to find the
+		 * correct head number by looking up the position of this
+		 * display controller's node within the device tree. Assuming
+		 * that the nodes are ordered properly in the DTS file and
+		 * that the translation into a flattened device tree blob
+		 * preserves that ordering this will actually yield the right
+		 * head number.
+		 *
+		 * If those assumptions don't hold, this will still work for
+		 * cases where only a single display controller is used.
+		 */
+		for_each_matching_node(np, tegra_dc_of_match) {
+			if (np == dc->dev->of_node)
+				break;
+
+			value++;
+		}
+	}
+
+	dc->pipe = value;
+
+	return 0;
+}
+
 static int tegra_dc_probe(struct platform_device *pdev)
 {
 	const struct of_device_id *id;
@@ -1207,6 +1240,10 @@ static int tegra_dc_probe(struct platform_device *pdev)
 	dc->dev = &pdev->dev;
 	dc->soc = id->data;
 
+	err = tegra_dc_parse_dt(dc);
+	if (err < 0)
+		return err;
+
 	dc->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(dc->clk)) {
 		dev_err(&pdev->dev, "failed to get clock\n");
diff --git a/drivers/gpu/drm/tegra/hdmi.c b/drivers/gpu/drm/tegra/hdmi.c
index bc9cb1ac709..6928015d11a 100644
--- a/drivers/gpu/drm/tegra/hdmi.c
+++ b/drivers/gpu/drm/tegra/hdmi.c
@@ -1418,9 +1418,6 @@ static int tegra_hdmi_probe(struct platform_device *pdev)
 		return err;
 
 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!regs)
-		return -ENXIO;
-
 	hdmi->regs = devm_ioremap_resource(&pdev->dev, regs);
 	if (IS_ERR(hdmi->regs))
 		return PTR_ERR(hdmi->regs);
diff --git a/drivers/gpu/drm/tegra/output.c b/drivers/gpu/drm/tegra/output.c
index f1b5030f55e..57cecbd18ca 100644
--- a/drivers/gpu/drm/tegra/output.c
+++ b/drivers/gpu/drm/tegra/output.c
@@ -18,6 +18,10 @@ static int tegra_connector_get_modes(struct drm_connector *connector)
 	struct edid *edid = NULL;
 	int err = 0;
 
+	/*
+	 * If the panel provides one or more modes, use them exclusively and
+	 * ignore any other means of obtaining a mode.
+	 */
 	if (output->panel) {
 		err = output->panel->funcs->get_modes(output->panel);
 		if (err > 0)
@@ -187,8 +191,7 @@ int tegra_output_probe(struct tegra_output *output)
 {
 	struct device_node *ddc, *panel;
 	enum of_gpio_flags flags;
-	size_t size;
-	int err;
+	int err, size;
 
 	if (!output->of_node)
 		output->of_node = output->dev->of_node;
diff --git a/drivers/gpu/drm/tegra/rgb.c b/drivers/gpu/drm/tegra/rgb.c
index 03885bb8dcc..338f7f6561d 100644
--- a/drivers/gpu/drm/tegra/rgb.c
+++ b/drivers/gpu/drm/tegra/rgb.c
@@ -258,7 +258,7 @@ int tegra_dc_rgb_init(struct drm_device *drm, struct tegra_dc *dc)
 	 * RGB outputs are an exception, so we make sure they can be attached
 	 * to only their parent display controller.
 	 */
-	rgb->output.encoder.possible_crtcs = 1 << dc->pipe;
+	rgb->output.encoder.possible_crtcs = drm_crtc_mask(&dc->base);
 
 	return 0;
 }