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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>usb_function_deactivate</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="USB Gadget API for Linux" /><link rel="up" href="ch03s05.html" title="Composite Device Framework" /><link rel="prev" href="re57.html" title="usb_add_function" /><link rel="next" href="re59.html" title="usb_function_activate" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>usb_function_deactivate</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="re57.html">Prev</a> </td><th width="60%" align="center">Composite Device Framework</th><td width="20%" align="right"> <a accesskey="n" href="re59.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="usb_function_deactivate"><a id="API-usb-function-deactivate"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>usb_function_deactivate —
prevent function and gadget enumeration
</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">usb_function_deactivate </b>(</code></td><td>struct usb_function * <var class="pdparam">function</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Arguments"><a id="id2999150"></a><h2>Arguments</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>function</code></em></span></dt><dd><p>
the function that isn't yet ready to respond
</p></dd></dl></div></div><div class="refsect1" title="Description"><a id="id2999177"></a><h2>Description</h2><p>
Blocks response of the gadget driver to host enumeration by
preventing the data line pullup from being activated. This is
normally called during <em class="parameter"><code>bind</code></em>() processing to change from the
initial <span class="quote">“<span class="quote">ready to respond</span>”</span> state, or when a required resource
becomes available.
</p><p>
For example, drivers that serve as a passthrough to a userspace
daemon can block enumeration unless that daemon (such as an OBEX,
MTP, or print server) is ready to handle host requests.
</p><p>
Not all systems support software control of their USB peripheral
data pullups.
</p><p>
Returns zero on success, else negative errno.
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