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authorLinus Torvalds <torvalds@linux-foundation.org>2009-09-21 09:03:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-21 09:03:10 -0700
commitc720f5655df159a630fa0290a0bd67c93e92b0bf (patch)
tree940d139d0ec1ff5201efddef6cc663166a8a2df3 /Documentation/DocBook/v4l/func-munmap.xml
parentMerge branch 'linux-next' of git://git.infradead.org/ubifs-2.6 (diff)
parentV4L/DVB (13033): pt1: Don't use a deprecated DMA_BIT_MASK macro (diff)
downloadlinux-dev-c720f5655df159a630fa0290a0bd67c93e92b0bf.tar.xz
linux-dev-c720f5655df159a630fa0290a0bd67c93e92b0bf.zip
Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6: (222 commits) V4L/DVB (13033): pt1: Don't use a deprecated DMA_BIT_MASK macro V4L/DVB (13029): radio-si4713: remove #include <linux/version.h> V4L/DVB (13027): go7007: convert printks to v4l2_info V4L/DVB (13026): s2250-board: Implement brightness and contrast controls V4L/DVB (13025): s2250-board: Fix memory leaks V4L/DVB (13024): go7007: Implement vidioc_g_std and vidioc_querystd V4L/DVB (13023): go7007: Merge struct gofh and go declarations V4L/DVB (13022): go7007: Fix mpeg controls V4L/DVB (13021): go7007: Fix whitespace and line lengths V4L/DVB (13020): go7007: Updates to Kconfig and Makefile V4L/DVB (13019): video: initial support for ADV7180 V4L/DVB (13018): kzalloc failure ignored in au8522_probe() V4L/DVB (13017): gspca: kmalloc failure ignored in sd_start() V4L/DVB (13016): kmalloc failure ignored in lgdt3304_attach() and s921_attach() V4L/DVB (13015): kmalloc failure ignored in m920x_firmware_download() V4L/DVB (13014): Add support for Compro VideoMate E800 (DVB-T part only) V4L/DVB (13013): FM TX: si4713: Kconfig: Fixed two typos. V4L/DVB (13012): uvc: introduce missing kfree V4L/DVB (13011): Change tuner type of BeholdTV cards V4L/DVB (13009): gspca - stv06xx-hdcs: Reduce exposure range ...
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+<refentry id="func-munmap">
+ <refmeta>
+ <refentrytitle>V4L2 munmap()</refentrytitle>
+ &manvol;
+ </refmeta>
+
+ <refnamediv>
+ <refname>v4l2-munmap</refname>
+ <refpurpose>Unmap device memory</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcsynopsisinfo>
+#include &lt;unistd.h&gt;
+#include &lt;sys/mman.h&gt;</funcsynopsisinfo>
+ <funcprototype>
+ <funcdef>int <function>munmap</function></funcdef>
+ <paramdef>void *<parameter>start</parameter></paramdef>
+ <paramdef>size_t <parameter>length</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+ <refsect1>
+ <title>Arguments</title>
+ <variablelist>
+ <varlistentry>
+ <term><parameter>start</parameter></term>
+ <listitem>
+ <para>Address of the mapped buffer as returned by the
+&func-mmap; function.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>length</parameter></term>
+ <listitem>
+ <para>Length of the mapped buffer. This must be the same
+value as given to <function>mmap()</function> and returned by the
+driver in the &v4l2-buffer; <structfield>length</structfield>
+field.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para>Unmaps a previously with the &func-mmap; function mapped
+buffer and frees it, if possible. <!-- ? This function (not freeing)
+has no impact on I/O in progress, specifically it does not imply
+&VIDIOC-STREAMOFF; to terminate I/O. Unmapped buffers can still be
+enqueued, dequeued or queried, they are just not accessible by the
+application.--></para>
+ </refsect1>
+
+ <refsect1>
+ <title>Return Value</title>
+
+ <para>On success <function>munmap()</function> returns 0, on
+failure -1 and the <varname>errno</varname> variable is set
+appropriately:</para>
+
+ <variablelist>
+ <varlistentry>
+ <term><errorcode>EINVAL</errorcode></term>
+ <listitem>
+ <para>The <parameter>start</parameter> or
+<parameter>length</parameter> is incorrect, or no buffers have been
+mapped yet.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+</refentry>
+
+<!--
+Local Variables:
+mode: sgml
+sgml-parent-document: "v4l2.sgml"
+indent-tabs-mode: nil
+End:
+-->