drm/modes: Add a switch to differentiate free standing options

Some extra command line options can be either specified without anything
else on the command line (basically all the force connection options), but
some other are only relevant when matched with a resolution (margin and
interlace).

Let's add a switch to restrict if needed the available option set.

Fixes: e08ab74 ("drm/modes: Rewrite the command line parser")
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Tested-by: Thomas Graichen <thomas.graichen@gmail.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190827115850.25731-1-mripard@kernel.org

drivers/gpu/drm/drm_modes.c

@@ -1454,6 +1454,7 @@ static int drm_mode_parse_cmdline_refresh(const char *str, char **end_ptr,
 }
 
 static int drm_mode_parse_cmdline_extra(const char *str, int length,
+					bool freestanding,
 					const struct drm_connector *connector,
 					struct drm_cmdline_mode *mode)
 {
@@ -1462,9 +1463,15 @@ static int drm_mode_parse_cmdline_extra(const char *str, int length,
 	for (i = 0; i < length; i++) {
 		switch (str[i]) {
 		case 'i':
+			if (freestanding)
+				return -EINVAL;
+
 			mode->interlace = true;
 			break;
 		case 'm':
+			if (freestanding)
+				return -EINVAL;
+
 			mode->margins = true;
 			break;
 		case 'D':
@@ -1542,6 +1549,7 @@ static int drm_mode_parse_cmdline_res_mode(const char *str, unsigned int length,
 			if (extras) {
 				int ret = drm_mode_parse_cmdline_extra(end_ptr + i,
 								       1,
+								       false,
 								       connector,
 								       mode);
 				if (ret)
@@ -1811,7 +1819,7 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
 	    extra_ptr != options_ptr) {
 		int len = strlen(name) - (extra_ptr - name);
 
-		ret = drm_mode_parse_cmdline_extra(extra_ptr, len,
+		ret = drm_mode_parse_cmdline_extra(extra_ptr, len, false,
 						   connector, mode);
 		if (ret)
 			return false;