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Based on kernel version 3.13. Page generated on 2014-01-20 22:02 EST.

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
56	linkend="experimental">experimental</link> interface and may change in
57	the future.</para>
58	    </note>
59	
60	    <para>For driver debugging purposes this ioctl allows test
61	applications to query the driver about the chips present on the TV
62	card. Regular applications must not use it. When you found a chip
63	specific bug, please contact the linux-media mailing list (&v4l-ml;)
64	so 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>
72	fields of a &v4l2-dbg-chip-info;
73	and call <constant>VIDIOC_DBG_G_CHIP_INFO</constant> with a pointer to
74	this structure. On success the driver stores information about the
75	selected chip in the <structfield>name</structfield> and
76	<structfield>flags</structfield> fields.</para>
77	
78	    <para>When <structfield>match.type</structfield> is
79	<constant>V4L2_CHIP_MATCH_BRIDGE</constant>,
80	<structfield>match.addr</structfield> selects the nth bridge 'chip'
81	on the TV card. You can enumerate all chips by starting at zero and
82	incrementing <structfield>match.addr</structfield> by one until
83	<constant>VIDIOC_DBG_G_CHIP_INFO</constant> fails with an &EINVAL;.
84	The number zero always selects the bridge chip itself, &eg; the chip
85	connected to the PCI or USB bus. Non-zero numbers identify specific
86	parts of the bridge chip such as an AC97 register block.</para>
87	
88	    <para>When <structfield>match.type</structfield> is
89	<constant>V4L2_CHIP_MATCH_SUBDEV</constant>,
90	<structfield>match.addr</structfield> selects the nth sub-device. This
91	allows you to enumerate over all sub-devices.</para>
92	
93	    <para>On success, the <structfield>name</structfield> field will
94	contain a chip name and the <structfield>flags</structfield> field will
95	contain <constant>V4L2_CHIP_FL_READABLE</constant> if the driver supports
96	reading registers from the device or <constant>V4L2_CHIP_FL_WRITABLE</constant>
97	if the driver supports writing registers to the device.</para>
98	
99	    <para>We recommended the <application>v4l2-dbg</application>
100	utility over calling this ioctl directly. It is available from the
101	LinuxTV v4l-dvb repository; see <ulink
102	url="http://linuxtv.org/repo/">http://linuxtv.org/repo/</ulink> for
103	access instructions.</para>
104	
105	    <!-- Note for convenience vidioc-dbg-g-register.sgml
106		 contains a duplicate of this table. -->
107	    <table pgwide="1" frame="none" id="name-v4l2-dbg-match">
108	      <title>struct <structname>v4l2_dbg_match</structname></title>
109	      <tgroup cols="4">
110		&cs-ustr;
111		<tbody valign="top">
112		  <row>
113		    <entry>__u32</entry>
114		    <entry><structfield>type</structfield></entry>
115		    <entry>See <xref linkend="name-chip-match-types" /> for a list of
116	possible types.</entry>
117		  </row>
118		  <row>
119		    <entry>union</entry>
120		    <entry>(anonymous)</entry>
121		  </row>
122		  <row>
123		    <entry></entry>
124		    <entry>__u32</entry>
125		    <entry><structfield>addr</structfield></entry>
126		    <entry>Match a chip by this number, interpreted according
127	to the <structfield>type</structfield> field.</entry>
128		  </row>
129		  <row>
130		    <entry></entry>
131		    <entry>char</entry>
132		    <entry><structfield>name[32]</structfield></entry>
133		    <entry>Match a chip by this name, interpreted according
134	to the <structfield>type</structfield> field. Currently unused.</entry>
135		  </row>
136		</tbody>
137	      </tgroup>
138	    </table>
139	
140	    <table pgwide="1" frame="none" id="v4l2-dbg-chip-info">
141	      <title>struct <structname>v4l2_dbg_chip_info</structname></title>
142	      <tgroup cols="3">
143		&cs-str;
144		<tbody valign="top">
145		  <row>
146		    <entry>struct v4l2_dbg_match</entry>
147		    <entry><structfield>match</structfield></entry>
148		    <entry>How to match the chip, see <xref linkend="name-v4l2-dbg-match" />.</entry>
149		  </row>
150		  <row>
151		    <entry>char</entry>
152		    <entry><structfield>name[32]</structfield></entry>
153		    <entry>The name of the chip.</entry>
154		  </row>
155		  <row>
156		    <entry>__u32</entry>
157		    <entry><structfield>flags</structfield></entry>
158		    <entry>Set by the driver. If <constant>V4L2_CHIP_FL_READABLE</constant>
159	is set, then the driver supports reading registers from the device. If
160	<constant>V4L2_CHIP_FL_WRITABLE</constant> is set, then it supports writing registers.</entry>
161		  </row>
162		  <row>
163		    <entry>__u32</entry>
164		    <entry><structfield>reserved[8]</structfield></entry>
165		    <entry>Reserved fields, both application and driver must set these to 0.</entry>
166		  </row>
167		</tbody>
168	      </tgroup>
169	    </table>
170	
171	    <!-- Note for convenience vidioc-dbg-g-register.sgml
172		 contains a duplicate of this table. -->
173	    <table pgwide="1" frame="none" id="name-chip-match-types">
174	      <title>Chip Match Types</title>
175	      <tgroup cols="3">
176		&cs-def;
177		<tbody valign="top">
178		  <row>
179		    <entry><constant>V4L2_CHIP_MATCH_BRIDGE</constant></entry>
180		    <entry>0</entry>
181		    <entry>Match the nth chip on the card, zero for the
182		    bridge chip. Does not match sub-devices.</entry>
183		  </row>
184		  <row>
185		    <entry><constant>V4L2_CHIP_MATCH_SUBDEV</constant></entry>
186		    <entry>4</entry>
187		    <entry>Match the nth sub-device.</entry>
188		  </row>
189		</tbody>
190	      </tgroup>
191	    </table>
192	  </refsect1>
193	
194	  <refsect1>
195	    &return-value;
196	
197	    <variablelist>
198	      <varlistentry>
199		<term><errorcode>EINVAL</errorcode></term>
200		<listitem>
201		  <para>The <structfield>match_type</structfield> is invalid or
202	no device could be matched.</para>
203		</listitem>
204	      </varlistentry>
205	     </variablelist>
206	  </refsect1>
207	</refentry>
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