diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index bae43938c8f6..9cbe8f5c9aca 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -567,9 +567,9 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
 	struct drm_mode_crtc *crtc_req = data;
 	struct drm_crtc *crtc;
 	struct drm_plane *plane;
-	struct drm_connector **connector_set = NULL, *connector;
-	struct drm_framebuffer *fb = NULL;
-	struct drm_display_mode *mode = NULL;
+	struct drm_connector **connector_set, *connector;
+	struct drm_framebuffer *fb;
+	struct drm_display_mode *mode;
 	struct drm_mode_set set;
 	uint32_t __user *set_connectors_ptr;
 	struct drm_modeset_acquire_ctx ctx;
@@ -598,6 +598,10 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
 	mutex_lock(&crtc->dev->mode_config.mutex);
 	drm_modeset_acquire_init(&ctx, DRM_MODESET_ACQUIRE_INTERRUPTIBLE);
 retry:
+	connector_set = NULL;
+	fb = NULL;
+	mode = NULL;
+
 	ret = drm_modeset_lock_all_ctx(crtc->dev, &ctx);
 	if (ret)
 		goto out;
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 3c9fc99648b7..ff0bfc65a8c1 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -113,6 +113,9 @@ static const struct edid_quirk {
 	/* AEO model 0 reports 8 bpc, but is a 6 bpc panel */
 	{ "AEO", 0, EDID_QUIRK_FORCE_6BPC },
 
+	/* BOE model on HP Pavilion 15-n233sl reports 8 bpc, but is a 6 bpc panel */
+	{ "BOE", 0x78b, EDID_QUIRK_FORCE_6BPC },
+
 	/* CPT panel of Asus UX303LA reports 8 bpc, but is a 6 bpc panel */
 	{ "CPT", 0x17df, EDID_QUIRK_FORCE_6BPC },
 
@@ -4279,7 +4282,7 @@ static void drm_parse_ycbcr420_deep_color_info(struct drm_connector *connector,
 	struct drm_hdmi_info *hdmi = &connector->display_info.hdmi;
 
 	dc_mask = db[7] & DRM_EDID_YCBCR420_DC_MASK;
-	hdmi->y420_dc_modes |= dc_mask;
+	hdmi->y420_dc_modes = dc_mask;
 }
 
 static void drm_parse_hdmi_forum_vsdb(struct drm_connector *connector,
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 515a7aec57ac..9628dd617826 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1580,6 +1580,25 @@ unlock:
 }
 EXPORT_SYMBOL(drm_fb_helper_ioctl);
 
+static bool drm_fb_pixel_format_equal(const struct fb_var_screeninfo *var_1,
+				      const struct fb_var_screeninfo *var_2)
+{
+	return var_1->bits_per_pixel == var_2->bits_per_pixel &&
+	       var_1->grayscale == var_2->grayscale &&
+	       var_1->red.offset == var_2->red.offset &&
+	       var_1->red.length == var_2->red.length &&
+	       var_1->red.msb_right == var_2->red.msb_right &&
+	       var_1->green.offset == var_2->green.offset &&
+	       var_1->green.length == var_2->green.length &&
+	       var_1->green.msb_right == var_2->green.msb_right &&
+	       var_1->blue.offset == var_2->blue.offset &&
+	       var_1->blue.length == var_2->blue.length &&
+	       var_1->blue.msb_right == var_2->blue.msb_right &&
+	       var_1->transp.offset == var_2->transp.offset &&
+	       var_1->transp.length == var_2->transp.length &&
+	       var_1->transp.msb_right == var_2->transp.msb_right;
+}
+
 /**
  * drm_fb_helper_check_var - implementation for &fb_ops.fb_check_var
  * @var: screeninfo to check
@@ -1590,7 +1609,6 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
 {
 	struct drm_fb_helper *fb_helper = info->par;
 	struct drm_framebuffer *fb = fb_helper->fb;
-	int depth;
 
 	if (var->pixclock != 0 || in_dbg_master())
 		return -EINVAL;
@@ -1610,72 +1628,15 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
 		return -EINVAL;
 	}
 
-	switch (var->bits_per_pixel) {
-	case 16:
-		depth = (var->green.length == 6) ? 16 : 15;
-		break;
-	case 32:
-		depth = (var->transp.length > 0) ? 32 : 24;
-		break;
-	default:
-		depth = var->bits_per_pixel;
-		break;
-	}
-
-	switch (depth) {
-	case 8:
-		var->red.offset = 0;
-		var->green.offset = 0;
-		var->blue.offset = 0;
-		var->red.length = 8;
-		var->green.length = 8;
-		var->blue.length = 8;
-		var->transp.length = 0;
-		var->transp.offset = 0;
-		break;
-	case 15:
-		var->red.offset = 10;
-		var->green.offset = 5;
-		var->blue.offset = 0;
-		var->red.length = 5;
-		var->green.length = 5;
-		var->blue.length = 5;
-		var->transp.length = 1;
-		var->transp.offset = 15;
-		break;
-	case 16:
-		var->red.offset = 11;
-		var->green.offset = 5;
-		var->blue.offset = 0;
-		var->red.length = 5;
-		var->green.length = 6;
-		var->blue.length = 5;
-		var->transp.length = 0;
-		var->transp.offset = 0;
-		break;
-	case 24:
-		var->red.offset = 16;
-		var->green.offset = 8;
-		var->blue.offset = 0;
-		var->red.length = 8;
-		var->green.length = 8;
-		var->blue.length = 8;
-		var->transp.length = 0;
-		var->transp.offset = 0;
-		break;
-	case 32:
-		var->red.offset = 16;
-		var->green.offset = 8;
-		var->blue.offset = 0;
-		var->red.length = 8;
-		var->green.length = 8;
-		var->blue.length = 8;
-		var->transp.length = 8;
-		var->transp.offset = 24;
-		break;
-	default:
+	/*
+	 * drm fbdev emulation doesn't support changing the pixel format at all,
+	 * so reject all pixel format changing requests.
+	 */
+	if (!drm_fb_pixel_format_equal(var, &info->var)) {
+		DRM_DEBUG("fbdev emulation doesn't support changing the pixel format\n");
 		return -EINVAL;
 	}
+
 	return 0;
 }
 EXPORT_SYMBOL(drm_fb_helper_check_var);
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index b25d12ef120a..e3c404833115 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -214,9 +214,9 @@ struct detailed_timing {
 #define DRM_EDID_HDMI_DC_Y444             (1 << 3)
 
 /* YCBCR 420 deep color modes */
-#define DRM_EDID_YCBCR420_DC_48		  (1 << 6)
-#define DRM_EDID_YCBCR420_DC_36		  (1 << 5)
-#define DRM_EDID_YCBCR420_DC_30		  (1 << 4)
+#define DRM_EDID_YCBCR420_DC_48		  (1 << 2)
+#define DRM_EDID_YCBCR420_DC_36		  (1 << 1)
+#define DRM_EDID_YCBCR420_DC_30		  (1 << 0)
 #define DRM_EDID_YCBCR420_DC_MASK (DRM_EDID_YCBCR420_DC_48 | \
 				    DRM_EDID_YCBCR420_DC_36 | \
 				    DRM_EDID_YCBCR420_DC_30)