drm/modes: Properly generate a drm_display_mode from a named mode

The framework will get the drm_display_mode from the drm_cmdline_mode it
got by parsing the video command line argument by calling
drm_connector_pick_cmdline_mode().

The heavy lifting will then be done by the
drm_mode_create_from_cmdline_mode() function.

In the case of the named modes though, there's no real code to make that
translation and we rely on the drivers to guess which actual display mode
we meant.

Let's modify drm_mode_create_from_cmdline_mode() to properly generate the
drm_display_mode we mean when passing a named mode.
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Tested-by: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
Acked-in-principle-or-something-like-that-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://lore.kernel.org/r/20220728-rpi-analog-tv-properties-v10-9-256dad125326@cerno.techSigned-off-by: Maxime Ripard <maxime@cerno.tech>

drivers/gpu/drm/drm_modes.c

@@ -2499,6 +2499,31 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
 }
 EXPORT_SYMBOL(drm_mode_parse_command_line_for_connector);
 
+static struct drm_display_mode *drm_named_mode(struct drm_device *dev,
+					       struct drm_cmdline_mode *cmd)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(drm_named_modes); i++) {
+		const struct drm_named_mode *named_mode = &drm_named_modes[i];
+
+		if (strcmp(cmd->name, named_mode->name))
+			continue;
+
+		if (!cmd->tv_mode_specified)
+			continue;
+
+		return drm_analog_tv_mode(dev,
+					  named_mode->tv_mode,
+					  named_mode->pixel_clock_khz * 1000,
+					  named_mode->xres,
+					  named_mode->yres,
+					  named_mode->flags & DRM_MODE_FLAG_INTERLACE);
+	}
+
+	return NULL;
+}
+
 /**
  * drm_mode_create_from_cmdline_mode - convert a command line modeline into a DRM display mode
  * @dev: DRM device to create the new mode for
@@ -2516,7 +2541,9 @@ drm_mode_create_from_cmdline_mode(struct drm_device *dev,
 	if (cmd->xres == 0 || cmd->yres == 0)
 		return NULL;
 
-	if (cmd->cvt)
+	if (strlen(cmd->name))
+		mode = drm_named_mode(dev, cmd);
+	else if (cmd->cvt)
 		mode = drm_cvt_mode(dev,
 				    cmd->xres, cmd->yres,
 				    cmd->refresh_specified ? cmd->refresh : 60,

drivers/gpu/drm/tests/drm_client_modeset_test.c

@@ -21,7 +21,26 @@ struct drm_client_modeset_test_priv {
 
 static int drm_client_modeset_connector_get_modes(struct drm_connector *connector)
 {
-	return drm_add_modes_noedid(connector, 1920, 1200);
+	struct drm_display_mode *mode;
+	int count;
+
+	count = drm_add_modes_noedid(connector, 1920, 1200);
+
+	mode = drm_mode_analog_ntsc_480i(connector->dev);
+	if (!mode)
+		return count;
+
+	drm_mode_probed_add(connector, mode);
+	count += 1;
+
+	mode = drm_mode_analog_pal_576i(connector->dev);
+	if (!mode)
+		return count;
+
+	drm_mode_probed_add(connector, mode);
+	count += 1;
+
+	return count;
 }
 
 static const struct drm_connector_helper_funcs drm_client_modeset_connector_helper_funcs = {
@@ -52,6 +71,9 @@ static int drm_client_modeset_test_init(struct kunit *test)
 
 	drm_connector_helper_add(&priv->connector, &drm_client_modeset_connector_helper_funcs);
 
+	priv->connector.interlace_allowed = true;
+	priv->connector.doublescan_allowed = true;
+
 	return 0;
 }
 
@@ -84,8 +106,68 @@ static void drm_test_pick_cmdline_res_1920_1080_60(struct kunit *test)
 	KUNIT_EXPECT_TRUE(test, drm_mode_equal(expected_mode, mode));
 }
 
+struct drm_connector_pick_cmdline_mode_test {
+	const char *cmdline;
+	struct drm_display_mode *(*func)(struct drm_device *drm);
+};
+
+#define TEST_CMDLINE(_cmdline, _fn)		\
+	{					\
+		.cmdline = _cmdline,		\
+		.func = _fn,			\
+	}
+
+static void drm_test_pick_cmdline_named(struct kunit *test)
+{
+	const struct drm_connector_pick_cmdline_mode_test *params = test->param_value;
+	struct drm_client_modeset_test_priv *priv = test->priv;
+	struct drm_device *drm = priv->drm;
+	struct drm_connector *connector = &priv->connector;
+	struct drm_cmdline_mode *cmdline_mode = &connector->cmdline_mode;
+	const struct drm_display_mode *expected_mode, *mode;
+	const char *cmdline = params->cmdline;
+	int ret;
+
+	KUNIT_ASSERT_TRUE(test,
+			  drm_mode_parse_command_line_for_connector(cmdline,
+								    connector,
+								    cmdline_mode));
+
+	mutex_lock(&drm->mode_config.mutex);
+	ret = drm_helper_probe_single_connector_modes(connector, 1920, 1080);
+	mutex_unlock(&drm->mode_config.mutex);
+	KUNIT_ASSERT_GT(test, ret, 0);
+
+	mode = drm_connector_pick_cmdline_mode(connector);
+	KUNIT_ASSERT_NOT_NULL(test, mode);
+
+	expected_mode = params->func(drm);
+	KUNIT_ASSERT_NOT_NULL(test, expected_mode);
+
+	KUNIT_EXPECT_TRUE(test, drm_mode_equal(expected_mode, mode));
+}
+
+static const
+struct drm_connector_pick_cmdline_mode_test drm_connector_pick_cmdline_mode_tests[] = {
+	TEST_CMDLINE("NTSC", drm_mode_analog_ntsc_480i),
+	TEST_CMDLINE("PAL", drm_mode_analog_pal_576i),
+};
+
+static void
+drm_connector_pick_cmdline_mode_desc(const struct drm_connector_pick_cmdline_mode_test *t,
+				     char *desc)
+{
+	sprintf(desc, "%s", t->cmdline);
+}
+
+KUNIT_ARRAY_PARAM(drm_connector_pick_cmdline_mode,
+		  drm_connector_pick_cmdline_mode_tests,
+		  drm_connector_pick_cmdline_mode_desc);
+
 static struct kunit_case drm_test_pick_cmdline_tests[] = {
 	KUNIT_CASE(drm_test_pick_cmdline_res_1920_1080_60),
+	KUNIT_CASE_PARAM(drm_test_pick_cmdline_named,
+			 drm_connector_pick_cmdline_mode_gen_params),
 	{}
 };