1<refentry id="vidioc-dbg-g-chip-info"> 2 <refmeta> 3 <refentrytitle>ioctl VIDIOC_DBG_G_CHIP_INFO</refentrytitle> 4 &manvol; 5 </refmeta> 6 7 <refnamediv> 8 <refname>VIDIOC_DBG_G_CHIP_INFO</refname> 9 <refpurpose>Identify the chips on a TV card</refpurpose> 10 </refnamediv> 11 12 <refsynopsisdiv> 13 <funcsynopsis> 14 <funcprototype> 15 <funcdef>int <function>ioctl</function></funcdef> 16 <paramdef>int <parameter>fd</parameter></paramdef> 17 <paramdef>int <parameter>request</parameter></paramdef> 18 <paramdef>struct v4l2_dbg_chip_info 19*<parameter>argp</parameter></paramdef> 20 </funcprototype> 21 </funcsynopsis> 22 </refsynopsisdiv> 23 24 <refsect1> 25 <title>Arguments</title> 26 27 <variablelist> 28 <varlistentry> 29 <term><parameter>fd</parameter></term> 30 <listitem> 31 <para>&fd;</para> 32 </listitem> 33 </varlistentry> 34 <varlistentry> 35 <term><parameter>request</parameter></term> 36 <listitem> 37 <para>VIDIOC_DBG_G_CHIP_INFO</para> 38 </listitem> 39 </varlistentry> 40 <varlistentry> 41 <term><parameter>argp</parameter></term> 42 <listitem> 43 <para></para> 44 </listitem> 45 </varlistentry> 46 </variablelist> 47 </refsect1> 48 49 <refsect1> 50 <title>Description</title> 51 52 <note> 53 <title>Experimental</title> 54 55 <para>This is an <link 56linkend="experimental">experimental</link> interface and may change in 57the future.</para> 58 </note> 59 60 <para>For driver debugging purposes this ioctl allows test 61applications to query the driver about the chips present on the TV 62card. Regular applications must not use it. When you found a chip 63specific bug, please contact the linux-media mailing list (&v4l-ml;) 64so it can be fixed.</para> 65 66 <para>Additionally the Linux kernel must be compiled with the 67<constant>CONFIG_VIDEO_ADV_DEBUG</constant> option to enable this ioctl.</para> 68 69 <para>To query the driver applications must initialize the 70<structfield>match.type</structfield> and 71<structfield>match.addr</structfield> or <structfield>match.name</structfield> 72fields of a &v4l2-dbg-chip-info; 73and call <constant>VIDIOC_DBG_G_CHIP_INFO</constant> with a pointer to 74this structure. On success the driver stores information about the 75selected chip in the <structfield>name</structfield> and 76<structfield>flags</structfield> fields. On failure the structure 77remains unchanged.</para> 78 79 <para>When <structfield>match.type</structfield> is 80<constant>V4L2_CHIP_MATCH_BRIDGE</constant>, 81<structfield>match.addr</structfield> selects the nth bridge 'chip' 82on the TV card. You can enumerate all chips by starting at zero and 83incrementing <structfield>match.addr</structfield> by one until 84<constant>VIDIOC_DBG_G_CHIP_INFO</constant> fails with an &EINVAL;. 85The number zero always selects the bridge chip itself, ⪚ the chip 86connected to the PCI or USB bus. Non-zero numbers identify specific 87parts of the bridge chip such as an AC97 register block.</para> 88 89 <para>When <structfield>match.type</structfield> is 90<constant>V4L2_CHIP_MATCH_SUBDEV</constant>, 91<structfield>match.addr</structfield> selects the nth sub-device. This 92allows you to enumerate over all sub-devices.</para> 93 94 <para>On success, the <structfield>name</structfield> field will 95contain a chip name and the <structfield>flags</structfield> field will 96contain <constant>V4L2_CHIP_FL_READABLE</constant> if the driver supports 97reading registers from the device or <constant>V4L2_CHIP_FL_WRITABLE</constant> 98if the driver supports writing registers to the device.</para> 99 100 <para>We recommended the <application>v4l2-dbg</application> 101utility over calling this ioctl directly. It is available from the 102LinuxTV v4l-dvb repository; see <ulink 103url="http://linuxtv.org/repo/">http://linuxtv.org/repo/</ulink> for 104access instructions.</para> 105 106 <!-- Note for convenience vidioc-dbg-g-register.sgml 107 contains a duplicate of this table. --> 108 <table pgwide="1" frame="none" id="name-v4l2-dbg-match"> 109 <title>struct <structname>v4l2_dbg_match</structname></title> 110 <tgroup cols="4"> 111 &cs-ustr; 112 <tbody valign="top"> 113 <row> 114 <entry>__u32</entry> 115 <entry><structfield>type</structfield></entry> 116 <entry>See <xref linkend="name-chip-match-types" /> for a list of 117possible types.</entry> 118 </row> 119 <row> 120 <entry>union</entry> 121 <entry>(anonymous)</entry> 122 </row> 123 <row> 124 <entry></entry> 125 <entry>__u32</entry> 126 <entry><structfield>addr</structfield></entry> 127 <entry>Match a chip by this number, interpreted according 128to the <structfield>type</structfield> field.</entry> 129 </row> 130 <row> 131 <entry></entry> 132 <entry>char</entry> 133 <entry><structfield>name[32]</structfield></entry> 134 <entry>Match a chip by this name, interpreted according 135to the <structfield>type</structfield> field.</entry> 136 </row> 137 </tbody> 138 </tgroup> 139 </table> 140 141 <table pgwide="1" frame="none" id="v4l2-dbg-chip-info"> 142 <title>struct <structname>v4l2_dbg_chip_info</structname></title> 143 <tgroup cols="3"> 144 &cs-str; 145 <tbody valign="top"> 146 <row> 147 <entry>struct v4l2_dbg_match</entry> 148 <entry><structfield>match</structfield></entry> 149 <entry>How to match the chip, see <xref linkend="name-v4l2-dbg-match" />.</entry> 150 </row> 151 <row> 152 <entry>char</entry> 153 <entry><structfield>name[32]</structfield></entry> 154 <entry>The name of the chip.</entry> 155 </row> 156 <row> 157 <entry>__u32</entry> 158 <entry><structfield>flags</structfield></entry> 159 <entry>Set by the driver. If <constant>V4L2_CHIP_FL_READABLE</constant> 160is set, then the driver supports reading registers from the device. If 161<constant>V4L2_CHIP_FL_WRITABLE</constant> is set, then it supports writing registers.</entry> 162 </row> 163 <row> 164 <entry>__u32</entry> 165 <entry><structfield>reserved[8]</structfield></entry> 166 <entry>Reserved fields, both application and driver must set these to 0.</entry> 167 </row> 168 </tbody> 169 </tgroup> 170 </table> 171 172 <!-- Note for convenience vidioc-dbg-g-register.sgml 173 contains a duplicate of this table. --> 174 <table pgwide="1" frame="none" id="name-chip-match-types"> 175 <title>Chip Match Types</title> 176 <tgroup cols="3"> 177 &cs-def; 178 <tbody valign="top"> 179 <row> 180 <entry><constant>V4L2_CHIP_MATCH_BRIDGE</constant></entry> 181 <entry>0</entry> 182 <entry>Match the nth chip on the card, zero for the 183 bridge chip. Does not match sub-devices.</entry> 184 </row> 185 <row> 186 <entry><constant>V4L2_CHIP_MATCH_I2C_DRIVER</constant></entry> 187 <entry>1</entry> 188 <entry>Match an &i2c; chip by its driver name. Can't be used with this ioctl.</entry> 189 </row> 190 <row> 191 <entry><constant>V4L2_CHIP_MATCH_I2C_ADDR</constant></entry> 192 <entry>2</entry> 193 <entry>Match a chip by its 7 bit &i2c; bus address. Can't be used with this ioctl.</entry> 194 </row> 195 <row> 196 <entry><constant>V4L2_CHIP_MATCH_AC97</constant></entry> 197 <entry>3</entry> 198 <entry>Match the nth anciliary AC97 chip. Can't be used with this ioctl.</entry> 199 </row> 200 <row> 201 <entry><constant>V4L2_CHIP_MATCH_SUBDEV</constant></entry> 202 <entry>4</entry> 203 <entry>Match the nth sub-device.</entry> 204 </row> 205 </tbody> 206 </tgroup> 207 </table> 208 </refsect1> 209 210 <refsect1> 211 &return-value; 212 213 <variablelist> 214 <varlistentry> 215 <term><errorcode>EINVAL</errorcode></term> 216 <listitem> 217 <para>The <structfield>match_type</structfield> is invalid or 218no device could be matched.</para> 219 </listitem> 220 </varlistentry> 221 </variablelist> 222 </refsect1> 223</refentry> 224