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Diffstat (limited to 'Documentation/DocBook/v4l/vidioc-dbg-g-register.xml')
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diff --git a/Documentation/DocBook/v4l/vidioc-dbg-g-register.xml b/Documentation/DocBook/v4l/vidioc-dbg-g-register.xml deleted file mode 100644 index 980c7f3..0000000 --- a/Documentation/DocBook/v4l/vidioc-dbg-g-register.xml +++ /dev/null @@ -1,275 +0,0 @@ -<refentry id="vidioc-dbg-g-register"> - <refmeta> - <refentrytitle>ioctl VIDIOC_DBG_G_REGISTER, VIDIOC_DBG_S_REGISTER</refentrytitle> - &manvol; - </refmeta> - - <refnamediv> - <refname>VIDIOC_DBG_G_REGISTER</refname> - <refname>VIDIOC_DBG_S_REGISTER</refname> - <refpurpose>Read or write hardware registers</refpurpose> - </refnamediv> - - <refsynopsisdiv> - <funcsynopsis> - <funcprototype> - <funcdef>int <function>ioctl</function></funcdef> - <paramdef>int <parameter>fd</parameter></paramdef> - <paramdef>int <parameter>request</parameter></paramdef> - <paramdef>struct v4l2_dbg_register *<parameter>argp</parameter></paramdef> - </funcprototype> - </funcsynopsis> - <funcsynopsis> - <funcprototype> - <funcdef>int <function>ioctl</function></funcdef> - <paramdef>int <parameter>fd</parameter></paramdef> - <paramdef>int <parameter>request</parameter></paramdef> - <paramdef>const struct v4l2_dbg_register -*<parameter>argp</parameter></paramdef> - </funcprototype> - </funcsynopsis> - </refsynopsisdiv> - - <refsect1> - <title>Arguments</title> - - <variablelist> - <varlistentry> - <term><parameter>fd</parameter></term> - <listitem> - <para>&fd;</para> - </listitem> - </varlistentry> - <varlistentry> - <term><parameter>request</parameter></term> - <listitem> - <para>VIDIOC_DBG_G_REGISTER, VIDIOC_DBG_S_REGISTER</para> - </listitem> - </varlistentry> - <varlistentry> - <term><parameter>argp</parameter></term> - <listitem> - <para></para> - </listitem> - </varlistentry> - </variablelist> - </refsect1> - - <refsect1> - <title>Description</title> - - <note> - <title>Experimental</title> - - <para>This is an <link linkend="experimental">experimental</link> -interface and may change in the future.</para> - </note> - - <para>For driver debugging purposes these ioctls allow test -applications to access hardware registers directly. Regular -applications must not use them.</para> - - <para>Since writing or even reading registers can jeopardize the -system security, its stability and damage the hardware, both ioctls -require superuser privileges. Additionally the Linux kernel must be -compiled with the <constant>CONFIG_VIDEO_ADV_DEBUG</constant> option -to enable these ioctls.</para> - - <para>To write a register applications must initialize all fields -of a &v4l2-dbg-register; and call -<constant>VIDIOC_DBG_S_REGISTER</constant> with a pointer to this -structure. The <structfield>match.type</structfield> and -<structfield>match.addr</structfield> or <structfield>match.name</structfield> -fields select a chip on the TV -card, the <structfield>reg</structfield> field specifies a register -number and the <structfield>val</structfield> field the value to be -written into the register.</para> - - <para>To read a register applications must initialize the -<structfield>match.type</structfield>, -<structfield>match.chip</structfield> or <structfield>match.name</structfield> and -<structfield>reg</structfield> fields, and call -<constant>VIDIOC_DBG_G_REGISTER</constant> with a pointer to this -structure. On success the driver stores the register value in the -<structfield>val</structfield> field. On failure the structure remains -unchanged.</para> - - <para>When <structfield>match.type</structfield> is -<constant>V4L2_CHIP_MATCH_HOST</constant>, -<structfield>match.addr</structfield> selects the nth non-&i2c; chip -on the TV card. The number zero always selects the host chip, ⪚ the -chip connected to the PCI or USB bus. You can find out which chips are -present with the &VIDIOC-DBG-G-CHIP-IDENT; ioctl.</para> - - <para>When <structfield>match.type</structfield> is -<constant>V4L2_CHIP_MATCH_I2C_DRIVER</constant>, -<structfield>match.name</structfield> contains the I2C driver name. -For instance -<constant>"saa7127"</constant> will match any chip -supported by the saa7127 driver, regardless of its &i2c; bus address. -When multiple chips supported by the same driver are present, the -effect of these ioctls is undefined. Again with the -&VIDIOC-DBG-G-CHIP-IDENT; ioctl you can find out which &i2c; chips are -present.</para> - - <para>When <structfield>match.type</structfield> is -<constant>V4L2_CHIP_MATCH_I2C_ADDR</constant>, -<structfield>match.addr</structfield> selects a chip by its 7 bit &i2c; -bus address.</para> - - <para>When <structfield>match.type</structfield> is -<constant>V4L2_CHIP_MATCH_AC97</constant>, -<structfield>match.addr</structfield> selects the nth AC97 chip -on the TV card.</para> - - <note> - <title>Success not guaranteed</title> - - <para>Due to a flaw in the Linux &i2c; bus driver these ioctls may -return successfully without actually reading or writing a register. To -catch the most likely failure we recommend a &VIDIOC-DBG-G-CHIP-IDENT; -call confirming the presence of the selected &i2c; chip.</para> - </note> - - <para>These ioctls are optional, not all drivers may support them. -However when a driver supports these ioctls it must also support -&VIDIOC-DBG-G-CHIP-IDENT;. Conversely it may support -<constant>VIDIOC_DBG_G_CHIP_IDENT</constant> but not these ioctls.</para> - - <para><constant>VIDIOC_DBG_G_REGISTER</constant> and -<constant>VIDIOC_DBG_S_REGISTER</constant> were introduced in Linux -2.6.21, but their API was changed to the one described here in kernel 2.6.29.</para> - - <para>We recommended the <application>v4l2-dbg</application> -utility over calling these ioctls directly. It is available from the -LinuxTV v4l-dvb repository; see <ulink -url="http://linuxtv.org/repo/">http://linuxtv.org/repo/</ulink> for -access instructions.</para> - - <!-- Note for convenience vidioc-dbg-g-chip-ident.sgml - contains a duplicate of this table. --> - <table pgwide="1" frame="none" id="v4l2-dbg-match"> - <title>struct <structname>v4l2_dbg_match</structname></title> - <tgroup cols="4"> - &cs-ustr; - <tbody valign="top"> - <row> - <entry>__u32</entry> - <entry><structfield>type</structfield></entry> - <entry>See <xref linkend="ident-chip-match-types" /> for a list of -possible types.</entry> - </row> - <row> - <entry>union</entry> - <entry>(anonymous)</entry> - </row> - <row> - <entry></entry> - <entry>__u32</entry> - <entry><structfield>addr</structfield></entry> - <entry>Match a chip by this number, interpreted according -to the <structfield>type</structfield> field.</entry> - </row> - <row> - <entry></entry> - <entry>char</entry> - <entry><structfield>name[32]</structfield></entry> - <entry>Match a chip by this name, interpreted according -to the <structfield>type</structfield> field.</entry> - </row> - </tbody> - </tgroup> - </table> - - - <table pgwide="1" frame="none" id="v4l2-dbg-register"> - <title>struct <structname>v4l2_dbg_register</structname></title> - <tgroup cols="4"> - <colspec colname="c1" /> - <colspec colname="c2" /> - <colspec colname="c4" /> - <tbody valign="top"> - <row> - <entry>struct v4l2_dbg_match</entry> - <entry><structfield>match</structfield></entry> - <entry>How to match the chip, see <xref linkend="v4l2-dbg-match" />.</entry> - </row> - <row> - <entry>__u64</entry> - <entry><structfield>reg</structfield></entry> - <entry>A register number.</entry> - </row> - <row> - <entry>__u64</entry> - <entry><structfield>val</structfield></entry> - <entry>The value read from, or to be written into the -register.</entry> - </row> - </tbody> - </tgroup> - </table> - - <!-- Note for convenience vidioc-dbg-g-chip-ident.sgml - contains a duplicate of this table. --> - <table pgwide="1" frame="none" id="chip-match-types"> - <title>Chip Match Types</title> - <tgroup cols="3"> - &cs-def; - <tbody valign="top"> - <row> - <entry><constant>V4L2_CHIP_MATCH_HOST</constant></entry> - <entry>0</entry> - <entry>Match the nth chip on the card, zero for the - host chip. Does not match &i2c; chips.</entry> - </row> - <row> - <entry><constant>V4L2_CHIP_MATCH_I2C_DRIVER</constant></entry> - <entry>1</entry> - <entry>Match an &i2c; chip by its driver name.</entry> - </row> - <row> - <entry><constant>V4L2_CHIP_MATCH_I2C_ADDR</constant></entry> - <entry>2</entry> - <entry>Match a chip by its 7 bit &i2c; bus address.</entry> - </row> - <row> - <entry><constant>V4L2_CHIP_MATCH_AC97</constant></entry> - <entry>3</entry> - <entry>Match the nth anciliary AC97 chip.</entry> - </row> - </tbody> - </tgroup> - </table> - </refsect1> - - <refsect1> - &return-value; - - <variablelist> - <varlistentry> - <term><errorcode>EINVAL</errorcode></term> - <listitem> - <para>The driver does not support this ioctl, or the kernel -was not compiled with the <constant>CONFIG_VIDEO_ADV_DEBUG</constant> -option, or the <structfield>match_type</structfield> is invalid, or the -selected chip or register does not exist.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><errorcode>EPERM</errorcode></term> - <listitem> - <para>Insufficient permissions. Root privileges are required -to execute these ioctls.</para> - </listitem> - </varlistentry> - </variablelist> - </refsect1> -</refentry> - -<!-- -Local Variables: -mode: sgml -sgml-parent-document: "v4l2.sgml" -indent-tabs-mode: nil -End: ---> |