linux-kernel - Re: [PATCH v2 09/41] drm/connector: Add TV standard property

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Date:   Mon, 5 Sep 2022 12:18:21 +0200
From:   Noralf Trønnes <noralf@...nnes.org>
To:     Maxime Ripard <maxime@...no.tech>,
        Maxime Ripard <mripard@...nel.org>,
        Ben Skeggs <bskeggs@...hat.com>,
        David Airlie <airlied@...ux.ie>, Chen-Yu Tsai <wens@...e.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Lyude Paul <lyude@...hat.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        Tvrtko Ursulin <tvrtko.ursulin@...ux.intel.com>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Samuel Holland <samuel@...lland.org>,
        Karol Herbst <kherbst@...hat.com>,
        Emma Anholt <emma@...olt.net>, Daniel Vetter <daniel@...ll.ch>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>
Cc:     Hans de Goede <hdegoede@...hat.com>,
        linux-arm-kernel@...ts.infradead.org,
        Phil Elwell <phil@...pberrypi.com>,
        intel-gfx@...ts.freedesktop.org,
        Dave Stevenson <dave.stevenson@...pberrypi.com>,
        dri-devel@...ts.freedesktop.org, Dom Cobley <dom@...pberrypi.com>,
        linux-kernel@...r.kernel.org, nouveau@...ts.freedesktop.org,
        linux-sunxi@...ts.linux.dev,
        Mateusz Kwiatkowski <kfyatek+publicgit@...il.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Noralf Trønnes <noralf@...nnes.org>
Subject: Re: [PATCH v2 09/41] drm/connector: Add TV standard property



Den 29.08.2022 15.11, skrev Maxime Ripard:
> The TV mode property has been around for a while now to select and get the
> 
> current TV mode output on an analog TV connector.
> 
> 
> 
> Despite that property name being generic, its content isn't and has been
> 
> driver-specific which makes it hard to build any generic behaviour on top
> 
> of it, both in kernel and user-space.
> 
> 
> 
> Let's create a new bitmask tv norm property, that can contain any of the
> 
> analog TV standards currently supported by kernel drivers. Each driver can
> 
> then pass in a bitmask of the modes it supports.
> 
> 
> 
> We'll then be able to phase out the older tv mode property.
> 
> 
> 
> Signed-off-by: Maxime Ripard <maxime@...no.tech>
> 
> 
> 

> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c

> +/**
> 
> + * drm_mode_create_tv_properties - create TV specific connector properties
> 
> + * @dev: DRM device
> 
> + * @supported_tv_modes: Bitmask of TV modes supported (See DRM_MODE_TV_MODE_*)
> 
> +
> 
> + * Called by a driver's TV initialization routine, this function creates
> 
> + * the TV specific connector properties for a given device.  Caller is
> 
> + * responsible for allocating a list of format names and passing them to
> 
> + * this routine.
> 
> + *
> 
> + * Returns:
> 
> + * 0 on success or a negative error code on failure.
> 
> + */
> 
> +int drm_mode_create_tv_properties(struct drm_device *dev,
> 
> +				  unsigned int supported_tv_modes)
> 
> +{
> 
> +	struct drm_prop_enum_list tv_mode_list[DRM_MODE_TV_MODE_MAX];
> 
> +	struct drm_property *tv_mode;
> 
> +	unsigned int i, len = 0;
> 
> +
> 

Can you add a check here like in the legacy version:

	if (dev->mode_config.tv_mode_property)
		return 0;

This way it's possible to call this multiple times. Like in drm/gud
during connector init if there are multiple TV connectors or if a device
with multiple IP blocks should show up.

Noralf.

> +	for (i = 0; i < DRM_MODE_TV_MODE_MAX; i++) {
> 
> +		if (!(supported_tv_modes & BIT(i)))
> 
> +			continue;
> 
> +
> 
> +		tv_mode_list[len].type = i;
> 
> +		tv_mode_list[len].name = drm_get_tv_mode_name(i);
> 
> +		len++;
> 
> +	}
> 
> +
> 
> +	tv_mode = drm_property_create_enum(dev, 0, "TV mode",
> 
> +					   tv_mode_list, len);
> 
> +	if (!tv_mode)
> 
> +		return -ENOMEM;
> 
> +
> 
> +	dev->mode_config.tv_mode_property = tv_mode;
> 
> +
> 
> +	return drm_mode_create_tv_properties_legacy(dev, 0, NULL);
> 
> +}
> 
> +EXPORT_SYMBOL(drm_mode_create_tv_properties);
>