diff --git a/drivers/gpu/drm/bridge/lontium-lt8912b.c b/drivers/gpu/drm/bridge/lontium-lt8912b.c
index e7c4bef..4b2ae27 100644
--- a/drivers/gpu/drm/bridge/lontium-lt8912b.c
+++ b/drivers/gpu/drm/bridge/lontium-lt8912b.c
@@ -441,23 +441,21 @@
 static int lt8912_connector_get_modes(struct drm_connector *connector)
 {
 	const struct drm_edid *drm_edid;
-	int ret = -1;
-	int num = 0;
 	struct lt8912 *lt = connector_to_lt8912(connector);
 	u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+	int ret, num;
 
 	drm_edid = drm_bridge_edid_read(lt->hdmi_port, connector);
 	drm_edid_connector_update(connector, drm_edid);
-	if (drm_edid) {
-		num = drm_edid_connector_add_modes(connector);
-	} else {
-		return ret;
-	}
+	if (!drm_edid)
+		return 0;
+
+	num = drm_edid_connector_add_modes(connector);
 
 	ret = drm_display_info_set_bus_formats(&connector->display_info,
 					       &bus_format, 1);
-	if (ret)
-		num = ret;
+	if (ret < 0)
+		num = 0;
 
 	drm_edid_free(drm_edid);
 	return num;
diff --git a/drivers/gpu/drm/bridge/lontium-lt9611uxc.c b/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
index bcf8bcc..f4f593a 100644
--- a/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
+++ b/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
@@ -294,8 +294,8 @@
 static int lt9611uxc_connector_get_modes(struct drm_connector *connector)
 {
 	struct lt9611uxc *lt9611uxc = connector_to_lt9611uxc(connector);
-	unsigned int count;
 	const struct drm_edid *drm_edid;
+	int count;
 
 	drm_edid = drm_bridge_edid_read(&lt9611uxc->bridge, connector);
 	drm_edid_connector_update(connector, drm_edid);
diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index e814020..cfbe020 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -274,19 +274,24 @@
  * The modes probed from the panel are automatically added to the connector
  * that the panel is attached to.
  *
- * Return: The number of modes available from the panel on success or a
- * negative error code on failure.
+ * Return: The number of modes available from the panel on success, or 0 on
+ * failure (no modes).
  */
 int drm_panel_get_modes(struct drm_panel *panel,
 			struct drm_connector *connector)
 {
 	if (!panel)
-		return -EINVAL;
+		return 0;
 
-	if (panel->funcs && panel->funcs->get_modes)
-		return panel->funcs->get_modes(panel, connector);
+	if (panel->funcs && panel->funcs->get_modes) {
+		int num;
 
-	return -EOPNOTSUPP;
+		num = panel->funcs->get_modes(panel, connector);
+		if (num > 0)
+			return num;
+	}
+
+	return 0;
 }
 EXPORT_SYMBOL(drm_panel_get_modes);
 
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 19ecb74..75f8475 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -422,6 +422,13 @@
 
 	count = connector_funcs->get_modes(connector);
 
+	/* The .get_modes() callback should not return negative values. */
+	if (count < 0) {
+		drm_err(connector->dev, ".get_modes() returned %pe\n",
+			ERR_PTR(count));
+		count = 0;
+	}
+
 	/*
 	 * Fallback for when DDC probe failed in drm_get_edid() and thus skipped
 	 * override/firmware EDID.
diff --git a/drivers/gpu/drm/exynos/exynos_dp.c b/drivers/gpu/drm/exynos/exynos_dp.c
index ca31bad..f48c434 100644
--- a/drivers/gpu/drm/exynos/exynos_dp.c
+++ b/drivers/gpu/drm/exynos/exynos_dp.c
@@ -74,16 +74,15 @@
 {
 	struct exynos_dp_device *dp = to_dp(plat_data);
 	struct drm_display_mode *mode;
-	int num_modes = 0;
 
 	if (dp->plat_data.panel)
-		return num_modes;
+		return 0;
 
 	mode = drm_mode_create(connector->dev);
 	if (!mode) {
 		DRM_DEV_ERROR(dp->dev,
 			      "failed to create a new display mode.\n");
-		return num_modes;
+		return 0;
 	}
 
 	drm_display_mode_from_videomode(&dp->vm, mode);
@@ -94,7 +93,7 @@
 	drm_mode_set_name(mode);
 	drm_mode_probed_add(connector, mode);
 
-	return num_modes + 1;
+	return 1;
 }
 
 static int exynos_dp_bridge_attach(struct analogix_dp_plat_data *plat_data,
diff --git a/drivers/gpu/drm/exynos/exynos_drm_vidi.c b/drivers/gpu/drm/exynos/exynos_drm_vidi.c
index 00382f2..f5bbba9 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_vidi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_vidi.c
@@ -316,14 +316,14 @@
 	 */
 	if (!ctx->raw_edid) {
 		DRM_DEV_DEBUG_KMS(ctx->dev, "raw_edid is null.\n");
-		return -EFAULT;
+		return 0;
 	}
 
 	edid_len = (1 + ctx->raw_edid->extensions) * EDID_LENGTH;
 	edid = kmemdup(ctx->raw_edid, edid_len, GFP_KERNEL);
 	if (!edid) {
 		DRM_DEV_DEBUG_KMS(ctx->dev, "failed to allocate edid\n");
-		return -ENOMEM;
+		return 0;
 	}
 
 	drm_connector_update_edid_property(connector, edid);
diff --git a/drivers/gpu/drm/exynos/exynos_hdmi.c b/drivers/gpu/drm/exynos/exynos_hdmi.c
index 43bed6cb..b1d02de 100644
--- a/drivers/gpu/drm/exynos/exynos_hdmi.c
+++ b/drivers/gpu/drm/exynos/exynos_hdmi.c
@@ -887,11 +887,11 @@
 	int ret;
 
 	if (!hdata->ddc_adpt)
-		return -ENODEV;
+		return 0;
 
 	edid = drm_get_edid(connector, hdata->ddc_adpt);
 	if (!edid)
-		return -ENODEV;
+		return 0;
 
 	hdata->dvi_mode = !connector->display_info.is_hdmi;
 	DRM_DEV_DEBUG_KMS(hdata->dev, "%s : width[%d] x height[%d]\n",
diff --git a/drivers/gpu/drm/imx/ipuv3/parallel-display.c b/drivers/gpu/drm/imx/ipuv3/parallel-display.c
index 7034973..55dedd7 100644
--- a/drivers/gpu/drm/imx/ipuv3/parallel-display.c
+++ b/drivers/gpu/drm/imx/ipuv3/parallel-display.c
@@ -72,14 +72,14 @@
 		int ret;
 
 		if (!mode)
-			return -EINVAL;
+			return 0;
 
 		ret = of_get_drm_display_mode(np, &imxpd->mode,
 					      &imxpd->bus_flags,
 					      OF_USE_NATIVE_MODE);
 		if (ret) {
 			drm_mode_destroy(connector->dev, mode);
-			return ret;
+			return 0;
 		}
 
 		drm_mode_copy(mode, &imxpd->mode);
diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index 56dcd25..db8cbf6 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -1256,6 +1256,8 @@
 			drm_vma_node_unmap(&nvbo->bo.base.vma_node,
 					   bdev->dev_mapping);
 			nouveau_ttm_io_mem_free_locked(drm, nvbo->bo.resource);
+			nvbo->bo.resource->bus.offset = 0;
+			nvbo->bo.resource->bus.addr = NULL;
 			goto retry;
 		}
 
diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c b/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c
index a64c813..c029e5d 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c
@@ -1432,6 +1432,10 @@
 
 /**
  * r535_gsp_msg_run_cpu_sequencer() -- process I/O commands from the GSP
+ * @priv: gsp pointer
+ * @fn: function number (ignored)
+ * @repv: pointer to libos print RPC
+ * @repc: message size
  *
  * The GSP sequencer is a list of I/O commands that the GSP can send to
  * the driver to perform for various purposes.  The most common usage is to
@@ -1783,6 +1787,7 @@
 
 /**
  * r535_gsp_libos_init() -- create the libos arguments structure
+ * @gsp: gsp pointer
  *
  * The logging buffers are byte queues that contain encoded printf-like
  * messages from GSP-RM.  They need to be decoded by a special application
@@ -1922,6 +1927,10 @@
 
 /**
  * nvkm_gsp_radix3_sg - build a radix3 table from a S/G list
+ * @gsp: gsp pointer
+ * @sgt: S/G list to traverse
+ * @size: size of the image, in bytes
+ * @rx3: radix3 array to update
  *
  * The GSP uses a three-level page table, called radix3, to map the firmware.
  * Each 64-bit "pointer" in the table is either the bus address of an entry in
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 34f807e..d8751ea2 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -509,7 +509,7 @@
 	edid = drm_get_edid(connector, vc4_hdmi->ddc);
 	cec_s_phys_addr_from_edid(vc4_hdmi->cec_adap, edid);
 	if (!edid)
-		return -ENODEV;
+		return 0;
 
 	drm_connector_update_edid_property(connector, edid);
 	ret = drm_add_edid_modes(connector, edid);
diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
index 881b03e..9ed4246 100644
--- a/include/drm/drm_modeset_helper_vtables.h
+++ b/include/drm/drm_modeset_helper_vtables.h
@@ -898,7 +898,8 @@
 	 *
 	 * RETURNS:
 	 *
-	 * The number of modes added by calling drm_mode_probed_add().
+	 * The number of modes added by calling drm_mode_probed_add(). Return 0
+	 * on failures (no modes) instead of negative error codes.
 	 */
 	int (*get_modes)(struct drm_connector *connector);