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