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<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
Written 2012 by David Herrmann <dh.herrmann@googlemail.com>
Dedicated to the Public Domain
-->
<refentry id="drmModeGetResources">
<refentryinfo>
<title>Direct Rendering Manager</title>
<productname>libdrm</productname>
<date>September 2012</date>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>David</firstname>
<surname>Herrmann</surname>
<email>dh.herrmann@googlemail.com</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>drmModeGetResources</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>drmModeGetResources</refname>
<refpurpose>retrieve current display configuration information</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include <xf86drm.h></funcsynopsisinfo>
<funcsynopsisinfo>#include <xf86drmMode.h></funcsynopsisinfo>
<funcprototype>
<funcdef>drmModeResPtr <function>drmModeGetResources</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>drmModeGetResources</function> allocates, populates, and
returns a <structname>drmModeRes</structname> structure containing
information about the current display configuration. The structure
contains the following fields:
<programlisting>
typedef struct _drmModeRes {
int count_fbs;
uint32_t *fbs;
int count_crtcs;
uint32_t *crtcs;
int count_connectors;
uint32_t *connectors;
int count_encoders;
uint32_t *encoders;
uint32_t min_width, max_width;
uint32_t min_height, max_height;
} drmModeRes, *drmModeResPtr;
</programlisting>
</para>
<para>The <structfield>count_fbs</structfield> and
<structfield>fbs</structfield> fields indicate the number of currently
allocated framebuffer objects (i.e., objects that can be attached to
a given CRTC or sprite for display).</para>
<para>The <structfield>count_crtcs</structfield> and
<structfield>crtcs</structfield> fields list the available CRTCs in
the configuration. A CRTC is simply an object that can scan out a
framebuffer to a display sink, and contains mode timing and relative
position information. CRTCs drive encoders, which are responsible for
converting the pixel stream into a specific display protocol (e.g.,
MIPI or HDMI).</para>
<para>The <structfield>count_connectors</structfield> and
<structfield>connectors</structfield> fields list the available
physical connectors on the system. Note that some of these may not be
exposed from the chassis (e.g., LVDS or eDP). Connectors are attached
to encoders and contain information about the attached display sink
(e.g., width and height in mm, subpixel ordering, and various other
properties).</para>
<para>The <structfield>count_encoders</structfield> and
<structfield>encoders</structfield> fields list the available encoders
on the device. Each encoder may be associated with a CRTC, and may be
used to drive a particular encoder.</para>
<para>The <structfield>min*</structfield> and
<structfield>max*</structfield> fields indicate the maximum size of a
framebuffer for this device (i.e., the scanout size limit).</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para><function>drmModeGetResources</function> returns a drmModeRes
structure pointer on success, <literal>NULL</literal> on failure. The
returned structure must be freed with
<citerefentry><refentrytitle>drmModeFreeResources</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
</refsect1>
<refsect1>
<title>Reporting Bugs</title>
<para>Bugs in this function should be reported to
http://bugs.freedesktop.org under the "Mesa" product, with "Other" or
"libdrm" as the component.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>drm</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
<citerefentry><refentrytitle>drm-kms</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
<citerefentry><refentrytitle>drmModeGetFB</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>drmModeAddFB</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>drmModeAddFB2</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>drmModeRmFB</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>drmModeDirtyFB</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>drmModeGetCrtc</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>drmModeSetCrtc</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>drmModeGetEncoder</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>drmModeGetConnector</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
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