drm/edid: Don't send bogus aspect ratios in AVI infoframes

If the user mode would specify an aspect ratio other than 4:3 or 16:9
we now silently ignore it. Maybe a better apporoach is to return an
error? Let's try that.

Also we must be careful that we don't try to send illegal picture
aspect in the infoframe as it's only capable of signalling none,
4:3, and 16:9. Currently we're sending these bogus infoframes
whenever the cea mode specifies some other aspect ratio.

Cc: Shashank Sharma <shashank.sharma@intel.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Jose Abreu <Jose.Abreu@synopsys.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1525777785-9740-5-git-send-email-ankit.k.nautiyal@intel.com

drivers/gpu/drm/drm_edid.c

@@ -4838,6 +4838,7 @@ drm_hdmi_avi_infoframe_from_display_mode(struct hdmi_avi_infoframe *frame,
 					 const struct drm_display_mode *mode,
 					 bool is_hdmi2_sink)
 {
+	enum hdmi_picture_aspect picture_aspect;
 	int err;
 
 	if (!frame || !mode)
@@ -4880,13 +4881,23 @@ drm_hdmi_avi_infoframe_from_display_mode(struct hdmi_avi_infoframe *frame,
 	 * Populate picture aspect ratio from either
 	 * user input (if specified) or from the CEA mode list.
 	 */
-	if (mode->picture_aspect_ratio == HDMI_PICTURE_ASPECT_4_3 ||
-		mode->picture_aspect_ratio == HDMI_PICTURE_ASPECT_16_9)
-		frame->picture_aspect = mode->picture_aspect_ratio;
-	else if (frame->video_code > 0)
-		frame->picture_aspect = drm_get_cea_aspect_ratio(
-						frame->video_code);
+	picture_aspect = mode->picture_aspect_ratio;
+	if (picture_aspect == HDMI_PICTURE_ASPECT_NONE)
+		picture_aspect = drm_get_cea_aspect_ratio(frame->video_code);
 
+	/*
+	 * The infoframe can't convey anything but none, 4:3
+	 * and 16:9, so if the user has asked for anything else
+	 * we can only satisfy it by specifying the right VIC.
+	 */
+	if (picture_aspect > HDMI_PICTURE_ASPECT_16_9) {
+		if (picture_aspect !=
+		    drm_get_cea_aspect_ratio(frame->video_code))
+			return -EINVAL;
+		picture_aspect = HDMI_PICTURE_ASPECT_NONE;
+	}
+
+	frame->picture_aspect = picture_aspect;
 	frame->active_aspect = HDMI_ACTIVE_ASPECT_PICTURE;
 	frame->scan_mode = HDMI_SCAN_MODE_UNDERSCAN;