1c0abf9e6Sopenharmony_ci<!-- HTML header for doxygen 1.8.8--> 2c0abf9e6Sopenharmony_ci<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3c0abf9e6Sopenharmony_ci<html xmlns="http://www.w3.org/1999/xhtml"> 4c0abf9e6Sopenharmony_ci <head> 5c0abf9e6Sopenharmony_ci <meta http-equiv="X-UA-Compatible" content="IE=edge"> 6c0abf9e6Sopenharmony_ci <!-- For Mobile Devices --> 7c0abf9e6Sopenharmony_ci <meta name="viewport" content="width=device-width, initial-scale=1"> 8c0abf9e6Sopenharmony_ci <meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/> 9c0abf9e6Sopenharmony_ci <meta name="generator" content="Doxygen 1.9.1"/> 10c0abf9e6Sopenharmony_ci <script type="text/javascript" src="https://code.jquery.com/jquery-2.1.1.min.js"></script> 11c0abf9e6Sopenharmony_ci <title>libevdev: Compatibility and Behavior across kernel versions</title> 12c0abf9e6Sopenharmony_ci <!--<link href="tabs.css" rel="stylesheet" type="text/css"/>--> 13c0abf9e6Sopenharmony_ci <script type="text/javascript" src="dynsections.js"></script> 14c0abf9e6Sopenharmony_ci <link href="search/search.css" rel="stylesheet" type="text/css"/> 15c0abf9e6Sopenharmony_ci<script type="text/javascript" src="search/searchdata.js"></script> 16c0abf9e6Sopenharmony_ci<script type="text/javascript" src="search/search.js"></script> 17c0abf9e6Sopenharmony_ci <link href="doxygen.css" rel="stylesheet" type="text/css" /> 18c0abf9e6Sopenharmony_ci <link href="bootstrap.css" rel="stylesheet" type="text/css"/> 19c0abf9e6Sopenharmony_ci<link href="customdoxygen.css" rel="stylesheet" type="text/css"/> 20c0abf9e6Sopenharmony_ci<link href="libevdevdoxygen.css" rel="stylesheet" type="text/css"/> 21c0abf9e6Sopenharmony_ci <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.1/js/bootstrap.min.js"></script> 22c0abf9e6Sopenharmony_ci <script type="text/javascript" src="doxy-boot.js"></script> 23c0abf9e6Sopenharmony_ci </head> 24c0abf9e6Sopenharmony_ci <body> 25c0abf9e6Sopenharmony_ci <nav class="navbar navbar-default" role="navigation"> 26c0abf9e6Sopenharmony_ci <div class="container"> 27c0abf9e6Sopenharmony_ci <div class="navbar-header"> 28c0abf9e6Sopenharmony_ci <a class="navbar-brand">libevdev 1.13.0</a> 29c0abf9e6Sopenharmony_ci </div> 30c0abf9e6Sopenharmony_ci </div> 31c0abf9e6Sopenharmony_ci </nav> 32c0abf9e6Sopenharmony_ci <div id="top"><!-- do not remove this div, it is closed by doxygen! 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Running libevdev on a kernel that is missing some feature will change libevdev's behavior. In most cases, the new behavior should be obvious, but it is spelled out below in detail.</p> 77c0abf9e6Sopenharmony_ci<h1><a class="anchor" id="autotoc_md14"></a> 78c0abf9e6Sopenharmony_ciMinimum requirements</h1> 79c0abf9e6Sopenharmony_ci<p>libevdev requires a 2.6.36 kernel as minimum. Specifically, it requires kernel-support for <code>ABS_MT_SLOT</code>.</p> 80c0abf9e6Sopenharmony_ci<h1><a class="anchor" id="autotoc_md15"></a> 81c0abf9e6Sopenharmony_ciEvent and input property names</h1> 82c0abf9e6Sopenharmony_ci<p>Event names and input property names are defined at build-time by the linux/input.h shipped with libevdev. The list of event names is compiled at build-time, any events not defined at build time will not resolve. Specifically, <a class="el" href="group__misc.html#gab407b3c2caaae502859c28460cad17bb">libevdev_event_code_get_name()</a> for an undefined type or code will always return <code>NULL</code>. Likewise, <a class="el" href="group__misc.html#gacc12bdb7b912070ac9c375428f2c9892">libevdev_property_get_name()</a> will return NULL for properties undefined at build-time.</p> 83c0abf9e6Sopenharmony_ci<h1><a class="anchor" id="autotoc_md16"></a> 84c0abf9e6Sopenharmony_ciInput properties</h1> 85c0abf9e6Sopenharmony_ci<p>If the kernel does not support input properties, specifically the <code>EVIOCGPROPS</code> ioctl, libevdev does not expose input properties to the caller. Specifically, <a class="el" href="group__bits.html#ga36d529ea53f4522004bc7d16c051464b">libevdev_has_property()</a> will always return 0 unless the property has been manually set with <a class="el" href="group__kernel.html#gafc552080520c9d886452b05f3a1d75b6">libevdev_enable_property()</a>.</p> 86c0abf9e6Sopenharmony_ci<p>This also applies to the libevdev-uinput code. If uinput does not honor <code>UI_SET_PROPBIT</code>, libevdev will continue without setting the properties on the device.</p> 87c0abf9e6Sopenharmony_ci<h1><a class="anchor" id="autotoc_md17"></a> 88c0abf9e6Sopenharmony_ciMT slot behavior</h1> 89c0abf9e6Sopenharmony_ci<p>If the kernel does not support the <code>EVIOCGMTSLOTS</code> ioctl, libevdev assumes all values in all slots are 0 and continues without an error.</p> 90c0abf9e6Sopenharmony_ci<h1><a class="anchor" id="autotoc_md18"></a> 91c0abf9e6Sopenharmony_ciSYN_DROPPED behavior</h1> 92c0abf9e6Sopenharmony_ci<p>A kernel without <code>SYN_DROPPED</code> won't send such an event. <a class="el" href="group__events.html#gabb96c864e836c0b98788f4ab771c3a76" title="Get the next event from the device.">libevdev_next_event()</a> will never require the switch to sync mode. </p> 93c0abf9e6Sopenharmony_ci</div></div><!-- contents --> 94c0abf9e6Sopenharmony_ci</div><!-- PageDoc --> 95c0abf9e6Sopenharmony_ci<!-- HTML footer for doxygen 1.8.8--> 96c0abf9e6Sopenharmony_ci<!-- start footer part --> 97c0abf9e6Sopenharmony_ci</div> 98c0abf9e6Sopenharmony_ci</div> 99c0abf9e6Sopenharmony_ci</div> 100c0abf9e6Sopenharmony_ci</div> 101c0abf9e6Sopenharmony_ci</div> 102c0abf9e6Sopenharmony_ci<hr class="footer"/><address class="footer"><small> 103c0abf9e6Sopenharmony_ciGenerated by  <a href="http://www.doxygen.org/index.html"> 104c0abf9e6Sopenharmony_ci<img class="footer" src="doxygen.png" alt="doxygen"/> 105c0abf9e6Sopenharmony_ci</a> 1.9.1 106c0abf9e6Sopenharmony_ci</small></address> 107c0abf9e6Sopenharmony_ci</body> 108c0abf9e6Sopenharmony_ci</html> 109
