asdk-libdrm

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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"

          "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

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<!--

  Written 2012 by David Herrmann <dh.herrmann@googlemail.com>

  Dedicated to the Public Domain

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<refentry id="drm">

  <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>drm</refentrytitle>

    <manvolnum>7</manvolnum>

  </refmeta>

​

  <refnamediv>

    <refname>drm</refname>

    <refpurpose>Direct Rendering Manager</refpurpose>

  </refnamediv>

​

  <refsynopsisdiv>

    <funcsynopsis>

      <funcsynopsisinfo>#include &lt;xf86drm.h&gt;</funcsynopsisinfo>

    </funcsynopsis>

  </refsynopsisdiv>

​

  <refsect1>

    <title>Description</title>

    <para>The <emphasis>Direct Rendering Manager</emphasis> (DRM) is a framework

          to manage <emphasis>Graphics Processing Units</emphasis> (GPUs). It is

          designed to support the needs of complex graphics devices, usually

          containing programmable pipelines well suited to 3D graphics

          acceleration. Furthermore, it is responsible for memory management,

          interrupt handling and DMA to provide a uniform interface to

          applications.</para>

​

    <para>In earlier days, the kernel framework was solely used to provide raw

          hardware access to priviledged user-space processes which implement

          all the hardware abstraction layers. But more and more tasks where

          moved into the kernel. All these interfaces are based on

          <citerefentry><refentrytitle>ioctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>

          commands on the DRM character device. The <emphasis>libdrm</emphasis>

          library provides wrappers for these system-calls and many helpers to

          simplify the API.</para>

​

    <para>When a GPU is detected, the DRM system loads a driver for the detected

          hardware type. Each connected GPU is then presented to user-space via

          a character-device that is usually available as

          <filename>/dev/dri/card0</filename> and can be accessed with