[PATCH 2/2] drm/doc: Document the KMS property API

Hans Verkuil hverkuil at xs4all.nl
Sat Jun 22 06:32:43 PDT 2013


Hi Laurent,

Is this a hint to me that V4L2 should have a property API as well? :-)

Anyway, I found some typos below:

On Sat June 22 2013 15:00:27 Laurent Pinchart wrote:
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
> ---
>  Documentation/DocBook/drm.tmpl | 143 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 143 insertions(+)
> 
> diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
> index cea420d..9d4bb06 100644
> --- a/Documentation/DocBook/drm.tmpl
> +++ b/Documentation/DocBook/drm.tmpl
> @@ -1236,6 +1236,15 @@ int max_width, max_height;</synopsis>
>            <title>Miscellaneous</title>
>            <itemizedlist>
>              <listitem>
> +              <synopsis>void (*set_property)(struct drm_crtc *crtc,
> +                     struct drm_property *property, uint64_t value);</synopsis>
> +              <para>
> +                Set the value of the given CRTC property to
> +                <parameter>value</parameter>. See <xref linkend="drm-kms-properties"/>
> +                for more information about properties.
> +              </para>
> +            </listitem>
> +            <listitem>
>                <synopsis>void (*gamma_set)(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
>                          uint32_t start, uint32_t size);</synopsis>
>                <para>
> @@ -1385,6 +1394,15 @@ int max_width, max_height;</synopsis>
>                <xref linkend="drm-kms-init"/>.
>              </para>
>            </listitem>
> +          <listitem>
> +            <synopsis>void (*set_property)(struct drm_plane *plane,
> +                     struct drm_property *property, uint64_t value);</synopsis>
> +            <para>
> +              Set the value of the given plane property to
> +              <parameter>value</parameter>. See <xref linkend="drm-kms-properties"/>
> +              for more information about properties.
> +            </para>
> +          </listitem>
>          </itemizedlist>
>        </sect3>
>      </sect2>
> @@ -1594,6 +1612,15 @@ int max_width, max_height;</synopsis>
>            <title>Miscellaneous</title>
>            <itemizedlist>
>              <listitem>
> +              <synopsis>void (*set_property)(struct drm_connector *connector,
> +                     struct drm_property *property, uint64_t value);</synopsis>
> +              <para>
> +                Set the value of the given connector property to
> +                <parameter>value</parameter>. See <xref linkend="drm-kms-properties"/>
> +                for more information about properties.
> +              </para>
> +            </listitem>
> +            <listitem>
>                <synopsis>void (*destroy)(struct drm_connector *connector);</synopsis>
>                <para>
>                  Destroy the connector when not needed anymore. See
> @@ -2187,6 +2214,122 @@ void intel_crt_init(struct drm_device *dev)
>      </sect2>
>    </sect1>
>  
> +  <!-- Internals: kms properties -->
> +
> +  <sect1 id="drm-kms-properties">
> +    <title>KMS Properties</title>
> +    <para>
> +      Drivers may need to expose additional parameters to applications than
> +      those described in the previous sections. KMS supports attaching
> +      properties to CRTCs, connectors and planes and offers a userspace API to
> +      list, get and set the property values.
> +    </para>
> +    <para>
> +      Properties are identified by a name that uniquely defines the property
> +      purpose, and store an associated value. For all property types except blob
> +      properties the value is a 64-bit unsigned integer.
> +    </para>
> +    <para>
> +      KMS differentiates between properties and property instances. Drivers
> +      first create properties and then create and associate individual instances
> +      of those properties to objects. A property can be instantiated multiple
> +      times and associated with different objects. Values are stored in property
> +      instances, and all other property information are stored in the propery
> +      and shared between all instances of the property.
> +    </para>
> +    <para>
> +      Every property is created with a type that influences how the KMS core
> +      handles the property. Supported property types are
> +      <variablelist>
> +        <varlistentry>
> +          <term>DRM_MODE_PROP_RANGE</term>
> +          <listitem><para>Ranges properties report their minimum and maximum

s/Ranges/Range/

> +            admissible values. The KMS core verifies that values set by
> +            application fit in that range.</para></listitem>
> +        </varlistentry>
> +        <varlistentry>
> +          <term>DRM_MODE_PROP_ENUM</term>
> +          <listitem><para>Enumerated properties take a numerical value that
> +            ranges from 0 to the number of enumered values defined by the

s/enumered/enumerated/

> +            property minus one, and associate a free-formed string name to each
> +            value. Application can retrieve the list of define value-name pairs

s/Application/Applications/
s/define/defined/

> +            and use the numerical value to get and set property instance values.
> +            </para></listitem>
> +        </varlistentry>
> +        <varlistentry>
> +          <term>DRM_MODE_PROP_BITMASK</term>
> +          <listitem><para>Bitmask properties are enumeration properties that
> +            additionally restrict all enumerated values to the 0..63 range.
> +            Bitmask property instance values combine one or more of the
> +            enumerated bits defined by the property.</para></listitem>
> +        </varlistentry>
> +        <varlistentry>
> +          <term>DRM_MODE_PROP_BLOB</term>
> +          <listitem><para>Blob properties store a binary blob without any format
> +            restriction. The binary blobs are created as KMS standalone objects,
> +            and blob property instance values store the ID of their associated
> +            blob object.</para>
> +	    <para>Blocb properties are only used for the connector EDID property

s/Blocb/Blob/

> +	    and cannot be created by drivers.</para></listitem>
> +        </varlistentry>
> +      </variablelist>
> +    </para>
> +    <para>
> +      To create a property drivers call one of the following functions depending
> +      on the property type. All property creation functions take property flags
> +      and name, as well as type-specific arguments.
> +      <itemizedlist>
> +        <listitem>
> +          <synopsis>struct drm_property *drm_property_create_range(struct drm_device *dev, int flags,
> +                                               const char *name,
> +                                               uint64_t min, uint64_t max);</synopsis>
> +          <para>Create a range property with the given minimum and maximum
> +            values.</para>
> +        </listitem>
> +        <listitem>
> +          <synopsis>struct drm_property *drm_property_create_enum(struct drm_device *dev, int flags,
> +                                              const char *name,
> +                                              const struct drm_prop_enum_list *props,
> +                                              int num_values);</synopsis>
> +          <para>Create an enumerated property. The <parameter>props</parameter>
> +            argument points to an array of <parameter>num_values</parameter>
> +            value-name pairs.</para>
> +        </listitem>
> +        <listitem>
> +          <synopsis>struct drm_property *drm_property_create_bitmask(struct drm_device *dev,
> +                                                 int flags, const char *name,
> +                                                 const struct drm_prop_enum_list *props,
> +                                                 int num_values);</synopsis>
> +          <para>Create a bitmask property. The <parameter>props</parameter>
> +            argument points to an array of <parameter>num_values</parameter>
> +            value-name pairs.</para>
> +        </listitem>
> +      </itemizedlist>
> +    </para>
> +    <para>
> +      Properties can additionally be created as immutable, in which case they
> +      will be read-only for applications but can be modified by the driver. To
> +      create an immutable property drivers must set the DRM_MODE_PROP_IMMUTABLE
> +      flag at property creation time.
> +    </para>
> +    <para>
> +      When no array of value-name pairs is readily available at property
> +      creation time for enumerated or range properties, drivers can create
> +      the property using the <function>drm_property_create</function> function
> +      and manually add enumeration value-name pairs by calling the
> +      <function>drm_property_add_enum</function> function. Care must be taken to
> +      properly specify the property type through the <parameter>flags</parameter>
> +      argument.
> +    </para>
> +    <para>
> +      After creating properties drivers can attach property instances to CRTC,
> +      connector and plane objects by calling the
> +      <function>drm_object_attach_property</function>. The function takes a
> +      pointer to the target object, a pointer to the previously created property
> +      and an initial instance value.
> +    </para>
> +  </sect1>
> +
>    <!-- Internals: vertical blanking -->
>  
>    <sect1 id="drm-vertical-blank">
> 

Regards,

	Hans


More information about the dri-devel mailing list