man/drmModeGetResources.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3           "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
   5 <!--
   6   Written 2012 by David Herrmann <dh.herrmann@googlemail.com>
   7   Dedicated to the Public Domain
   8 -->
   9
  10 <refentry id="drmModeGetResources">
  11   <refentryinfo>
  12     <title>Direct Rendering Manager</title>
  13     <productname>libdrm</productname>
  14     <date>September 2012</date>
  15     <authorgroup>
  16       <author>
  17         <contrib>Developer</contrib>
  18         <firstname>David</firstname>
  19         <surname>Herrmann</surname>
  20         <email>dh.herrmann@googlemail.com</email>
  21       </author>
  22     </authorgroup>
  23   </refentryinfo>
  24
  25   <refmeta>
  26     <refentrytitle>drmModeGetResources</refentrytitle>
  27     <manvolnum>3</manvolnum>
  28   </refmeta>
  29
  30   <refnamediv>
  31     <refname>drmModeGetResources</refname>
  32     <refpurpose>retrieve current display configuration information</refpurpose>
  33   </refnamediv>
  34
  35   <refsynopsisdiv>
  36
  37     <funcsynopsis>
  38       <funcsynopsisinfo>#include &lt;xf86drm.h&gt;</funcsynopsisinfo>
  39       <funcsynopsisinfo>#include &lt;xf86drmMode.h&gt;</funcsynopsisinfo>
  40
  41       <funcprototype>
  42         <funcdef>drmModeResPtr <function>drmModeGetResources</function></funcdef>
  43         <paramdef>int <parameter>fd</parameter></paramdef>
  44       </funcprototype>
  45     </funcsynopsis>
  46
  47   </refsynopsisdiv>
  48
  49   <refsect1>
  50     <title>Description</title>
  51     <para><function>drmModeGetResources</function> allocates, populates, and
  52           returns a <structname>drmModeRes</structname> structure containing
  53           information about the current display configuration. The structure
  54           contains the following fields:
  55
  56 <programlisting>
  57 typedef struct _drmModeRes {
  58     int count_fbs;
  59     uint32_t *fbs;
  60
  61     int count_crtcs;
  62     uint32_t *crtcs;
  63
  64     int count_connectors;
  65     uint32_t *connectors;
  66
  67     int count_encoders;
  68     uint32_t *encoders;
  69
  70     uint32_t min_width, max_width;
  71     uint32_t min_height, max_height;
  72 } drmModeRes, *drmModeResPtr;
  73 </programlisting>
  74
  75           </para>
  76
  77     <para>The <structfield>count_fbs</structfield> and
  78           <structfield>fbs</structfield> fields indicate the number of currently
  79           allocated framebuffer objects (i.e., objects that can be attached to
  80           a given CRTC or sprite for display).</para>
  81
  82     <para>The <structfield>count_crtcs</structfield> and
  83           <structfield>crtcs</structfield> fields list the available CRTCs in
  84           the configuration. A CRTC is simply an object that can scan out a
  85           framebuffer to a display sink, and contains mode timing and relative
  86           position information. CRTCs drive encoders, which are responsible for
  87           converting the pixel stream into a specific display protocol (e.g.,
  88           MIPI or HDMI).</para>
  89
  90     <para>The <structfield>count_connectors</structfield> and
  91           <structfield>connectors</structfield> fields list the available
  92           physical connectors on the system. Note that some of these may not be
  93           exposed from the chassis (e.g., LVDS or eDP). Connectors are attached
  94           to encoders and contain information about the attached display sink
  95           (e.g., width and height in mm, subpixel ordering, and various other
  96           properties).</para>
  97
  98     <para>The <structfield>count_encoders</structfield> and
  99           <structfield>encoders</structfield> fields list the available encoders
 100           on the device. Each encoder may be associated with a CRTC, and may be
 101           used to drive a particular encoder.</para>
 102
 103     <para>The <structfield>min*</structfield> and
 104           <structfield>max*</structfield> fields indicate the maximum size of a
 105           framebuffer for this device (i.e., the scanout size limit).</para>
 106   </refsect1>
 107
 108   <refsect1>
 109     <title>Return Value</title>
 110     <para><function>drmModeGetResources</function> returns a drmModeRes
 111           structure pointer on success, <literal>NULL</literal> on failure. The
 112           returned structure must be freed with
 113           <citerefentry><refentrytitle>drmModeFreeResources</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
 114   </refsect1>
 115
 116   <refsect1>
 117     <title>Reporting Bugs</title>
 118     <para>Bugs in this function should be reported to
 119       https://bugs.freedesktop.org/enter_bug.cgi?product=DRI&amp;component=libdrm
 120       under the "DRI" product, component "libdrm"</para>
 121   </refsect1>
 122
 123   <refsect1>
 124     <title>See Also</title>
 125     <para>
 126       <citerefentry><refentrytitle>drm</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 127       <citerefentry><refentrytitle>drm-kms</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 128       <citerefentry><refentrytitle>drmModeGetFB</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 129       <citerefentry><refentrytitle>drmModeAddFB</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 130       <citerefentry><refentrytitle>drmModeAddFB2</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 131       <citerefentry><refentrytitle>drmModeRmFB</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 132       <citerefentry><refentrytitle>drmModeDirtyFB</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 133       <citerefentry><refentrytitle>drmModeGetCrtc</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 134       <citerefentry><refentrytitle>drmModeSetCrtc</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 135       <citerefentry><refentrytitle>drmModeGetEncoder</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 136       <citerefentry><refentrytitle>drmModeGetConnector</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 137     </para>
 138   </refsect1>
 139 </refentry>