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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>Registration and Release</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="Writing an ALSA Driver" /><link rel="up" href="ch03.html" title="Chapter 3. Management of Cards and Components" /><link rel="prev" href="ch03s03.html" title="Chip-Specific Data" /><link rel="next" href="ch04.html" title="Chapter 4. PCI Resource Management" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Registration and Release</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch03s03.html">Prev</a> </td><th width="60%" align="center">Chapter 3. Management of Cards and Components</th><td width="20%" align="right"> <a accesskey="n" href="ch04.html">Next</a></td></tr></table><hr /></div><div class="section" title="Registration and Release"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="card-management-registration"></a>Registration and Release</h2></div></div></div><p>
After all components are assigned, register the card instance
by calling <code class="function">snd_card_register()</code>. Access
to the device files is enabled at this point. That is, before
<code class="function">snd_card_register()</code> is called, the
components are safely inaccessible from external side. If this
call fails, exit the probe function after releasing the card via
<code class="function">snd_card_free()</code>.
</p><p>
For releasing the card instance, you can call simply
<code class="function">snd_card_free()</code>. As mentioned earlier, all
components are released automatically by this call.
</p><p>
As further notes, the destructors (both
<code class="function">snd_mychip_dev_free</code> and
<code class="function">snd_mychip_free</code>) cannot be defined with
the <em class="parameter"><code>__devexit</code></em> prefix, because they may be
called from the constructor, too, at the false path.
</p><p>
For a device which allows hotplugging, you can use
<code class="function">snd_card_free_when_closed</code>. This one will
postpone the destruction until all devices are closed.
</p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ch03s03.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch03.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ch04.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chip-Specific Data </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 4. PCI Resource Management</td></tr></table></div></body></html>
