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Message-ID: <9e9a8a48-89f2-35d4-b26f-afa7cc44f2f6@tronnes.org>
Date:   Mon, 7 Nov 2022 18:49:57 +0100
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Subject: Re: [PATCH v7 14/23] drm/modes: Properly generate a drm_display_mode
 from a named mode
To:     Maxime Ripard <maxime@cerno.tech>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
        Ben Skeggs <bskeggs@redhat.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Samuel Holland <samuel@sholland.org>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Emma Anholt <emma@anholt.net>,
        Karol Herbst <kherbst@redhat.com>,
        Daniel Vetter <daniel@ffwll.ch>, Chen-Yu Tsai <wens@csie.org>,
        Lyude Paul <lyude@redhat.com>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        David Airlie <airlied@linux.ie>
Cc:     Phil Elwell <phil@raspberrypi.com>,
        Hans de Goede <hdegoede@redhat.com>,
        linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Dave Stevenson <dave.stevenson@raspberrypi.com>,
        linux-arm-kernel@lists.infradead.org,
        Dom Cobley <dom@raspberrypi.com>,
        Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>,
        dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org,
        nouveau@lists.freedesktop.org,
        =?UTF-8?Q?Noralf_Tr=c3=b8nnes?= <noralf@tronnes.org>
References: <20220728-rpi-analog-tv-properties-v7-0-7072a478c6b3@cerno.tech>
 <20220728-rpi-analog-tv-properties-v7-14-7072a478c6b3@cerno.tech>
From:   =?UTF-8?Q?Noralf_Tr=c3=b8nnes?= <noralf@tronnes.org>
In-Reply-To: <20220728-rpi-analog-tv-properties-v7-14-7072a478c6b3@cerno.tech>
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Den 07.11.2022 15.16, skrev Maxime Ripard:
> 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.
> 
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> 
> ---
> Changes in v7:
> - Use tv_mode_specified in drm_mode_parse_command_line_for_connector
> 
> Changes in v6:
> - Fix get_modes to return 0 instead of an error code
> - Rename the tests to follow the DRM test naming convention
> 
> Changes in v5:
> - Switched to KUNIT_ASSERT_NOT_NULL
> ---
>  drivers/gpu/drm/drm_modes.c                     | 34 ++++++++++-
>  drivers/gpu/drm/tests/drm_client_modeset_test.c | 77 ++++++++++++++++++++++++-
>  2 files changed, 109 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
> index dc037f7ceb37..49441cabdd9d 100644
> --- a/drivers/gpu/drm/drm_modes.c
> +++ b/drivers/gpu/drm/drm_modes.c
> @@ -2497,6 +2497,36 @@ 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)
> +{
> +	struct drm_display_mode *mode;
> +	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;

Only a named mode will set cmd->name, so is this check necessary?

> +
> +		mode = 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);
> +		if (!mode)
> +			return NULL;
> +
> +		return mode;

You can just return the result from drm_analog_tv_mode() directly.

With those considered:

Reviewed-by: Noralf Trønnes <noralf@tronnes.org>

> +	}
> +
> +	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
> @@ -2514,7 +2544,9 @@ 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,
> diff --git a/drivers/gpu/drm/tests/drm_client_modeset_test.c b/drivers/gpu/drm/tests/drm_client_modeset_test.c
> index 3aa1acfe75df..fdfe9e20702e 100644
> --- a/drivers/gpu/drm/tests/drm_client_modeset_test.c
> +++ b/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;
>  
>  }
> @@ -85,9 +107,62 @@ static void drm_test_pick_cmdline_res_1920_1080_60(struct kunit *test)
>  	KUNIT_EXPECT_TRUE(test, drm_mode_equal(expected_mode, mode));
>  }
>  
> +static void drm_test_pick_cmdline_named_ntsc(struct kunit *test)
> +{
> +	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;
> +	struct drm_display_mode *mode;
> +	const char *cmdline = "NTSC";
> +	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);
> +
> +	KUNIT_EXPECT_TRUE(test, drm_mode_equal(drm_mode_analog_ntsc_480i(drm), mode));
> +}
> +
> +static void drm_test_pick_cmdline_named_pal(struct kunit *test)
> +{
> +	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;
> +	struct drm_display_mode *mode;
> +	const char *cmdline = "PAL";
> +	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);
> +
> +	KUNIT_EXPECT_TRUE(test, drm_mode_equal(drm_mode_analog_pal_576i(drm), mode));
> +}
>  
>  static struct kunit_case drm_test_pick_cmdline_tests[] = {
>  	KUNIT_CASE(drm_test_pick_cmdline_res_1920_1080_60),
> +	KUNIT_CASE(drm_test_pick_cmdline_named_ntsc),
> +	KUNIT_CASE(drm_test_pick_cmdline_named_pal),
>  	{}
>  };
>  
>