1<refentry id="vidioc-g-dv-timings">
2  <refmeta>
3    <refentrytitle>ioctl VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS</refentrytitle>
4    &manvol;
5  </refmeta>
6
7  <refnamediv>
8    <refname>VIDIOC_G_DV_TIMINGS</refname>
9    <refname>VIDIOC_S_DV_TIMINGS</refname>
10    <refpurpose>Get or set custom DV timings for input or output</refpurpose>
11  </refnamediv>
12
13  <refsynopsisdiv>
14    <funcsynopsis>
15      <funcprototype>
16	<funcdef>int <function>ioctl</function></funcdef>
17	<paramdef>int <parameter>fd</parameter></paramdef>
18	<paramdef>int <parameter>request</parameter></paramdef>
19	<paramdef>struct v4l2_dv_timings *<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_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS</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    <para>To set custom DV timings for the input or output, applications use the
52<constant>VIDIOC_S_DV_TIMINGS</constant> ioctl and to get the current custom timings,
53applications use the <constant>VIDIOC_G_DV_TIMINGS</constant> ioctl. The detailed timing
54information is filled in using the structure &v4l2-dv-timings;. These ioctls take
55a pointer to the &v4l2-dv-timings; structure as argument. If the ioctl is not supported
56or the timing values are not correct, the driver returns &EINVAL;.</para>
57  </refsect1>
58
59  <refsect1>
60    &return-value;
61
62    <variablelist>
63      <varlistentry>
64	<term><errorcode>EINVAL</errorcode></term>
65	<listitem>
66	  <para>This ioctl is not supported, or the
67<constant>VIDIOC_S_DV_TIMINGS</constant> parameter was unsuitable.</para>
68	</listitem>
69      </varlistentry>
70      <varlistentry>
71	<term><errorcode>EBUSY</errorcode></term>
72	<listitem>
73	  <para>The device is busy and therefore can not change the timings.</para>
74	</listitem>
75      </varlistentry>
76    </variablelist>
77
78    <table pgwide="1" frame="none" id="v4l2-bt-timings">
79      <title>struct <structname>v4l2_bt_timings</structname></title>
80      <tgroup cols="3">
81	&cs-str;
82	<tbody valign="top">
83	  <row>
84	    <entry>__u32</entry>
85	    <entry><structfield>width</structfield></entry>
86	    <entry>Width of the active video in pixels</entry>
87	  </row>
88	  <row>
89	    <entry>__u32</entry>
90	    <entry><structfield>height</structfield></entry>
91	    <entry>Height of the active video in lines</entry>
92	  </row>
93	  <row>
94	    <entry>__u32</entry>
95	    <entry><structfield>interlaced</structfield></entry>
96	    <entry>Progressive (0) or interlaced (1)</entry>
97	  </row>
98	  <row>
99	    <entry>__u32</entry>
100	    <entry><structfield>polarities</structfield></entry>
101	    <entry>This is a bit mask that defines polarities of sync signals.
102bit 0 (V4L2_DV_VSYNC_POS_POL) is for vertical sync polarity and bit 1 (V4L2_DV_HSYNC_POS_POL) is for horizontal sync polarity. If the bit is set
103(1) it is positive polarity and if is cleared (0), it is negative polarity.</entry>
104	  </row>
105	  <row>
106	    <entry>__u64</entry>
107	    <entry><structfield>pixelclock</structfield></entry>
108	    <entry>Pixel clock in Hz. Ex. 74.25MHz->74250000</entry>
109	  </row>
110	  <row>
111	    <entry>__u32</entry>
112	    <entry><structfield>hfrontporch</structfield></entry>
113	    <entry>Horizontal front porch in pixels</entry>
114	  </row>
115	  <row>
116	    <entry>__u32</entry>
117	    <entry><structfield>hsync</structfield></entry>
118	    <entry>Horizontal sync length in pixels</entry>
119	  </row>
120	  <row>
121	    <entry>__u32</entry>
122	    <entry><structfield>hbackporch</structfield></entry>
123	    <entry>Horizontal back porch in pixels</entry>
124	  </row>
125	  <row>
126	    <entry>__u32</entry>
127	    <entry><structfield>vfrontporch</structfield></entry>
128	    <entry>Vertical front porch in lines</entry>
129	  </row>
130	  <row>
131	    <entry>__u32</entry>
132	    <entry><structfield>vsync</structfield></entry>
133	    <entry>Vertical sync length in lines</entry>
134	  </row>
135	  <row>
136	    <entry>__u32</entry>
137	    <entry><structfield>vbackporch</structfield></entry>
138	    <entry>Vertical back porch in lines</entry>
139	  </row>
140	  <row>
141	    <entry>__u32</entry>
142	    <entry><structfield>il_vfrontporch</structfield></entry>
143	    <entry>Vertical front porch in lines for bottom field of interlaced field formats</entry>
144	  </row>
145	  <row>
146	    <entry>__u32</entry>
147	    <entry><structfield>il_vsync</structfield></entry>
148	    <entry>Vertical sync length in lines for bottom field of interlaced field formats</entry>
149	  </row>
150	  <row>
151	    <entry>__u32</entry>
152	    <entry><structfield>il_vbackporch</structfield></entry>
153	    <entry>Vertical back porch in lines for bottom field of interlaced field formats</entry>
154	  </row>
155	</tbody>
156      </tgroup>
157    </table>
158
159    <table pgwide="1" frame="none" id="v4l2-dv-timings">
160      <title>struct <structname>v4l2_dv_timings</structname></title>
161      <tgroup cols="4">
162	&cs-str;
163	<tbody valign="top">
164	  <row>
165	    <entry>__u32</entry>
166	    <entry><structfield>type</structfield></entry>
167	    <entry></entry>
168	    <entry>Type of DV timings as listed in <xref linkend="dv-timing-types"/>.</entry>
169	  </row>
170	  <row>
171	    <entry>union</entry>
172	    <entry><structfield></structfield></entry>
173	    <entry></entry>
174	  </row>
175	  <row>
176	    <entry></entry>
177	    <entry>&v4l2-bt-timings;</entry>
178	    <entry><structfield>bt</structfield></entry>
179	    <entry>Timings defined by BT.656/1120 specifications</entry>
180	  </row>
181	  <row>
182	    <entry></entry>
183	    <entry>__u32</entry>
184	    <entry><structfield>reserved</structfield>[32]</entry>
185	    <entry></entry>
186	  </row>
187	</tbody>
188      </tgroup>
189    </table>
190
191    <table pgwide="1" frame="none" id="dv-timing-types">
192      <title>DV Timing types</title>
193      <tgroup cols="3">
194	&cs-str;
195	<tbody valign="top">
196	  <row>
197	    <entry>Timing type</entry>
198	    <entry>value</entry>
199	    <entry>Description</entry>
200	  </row>
201	  <row>
202	    <entry></entry>
203	    <entry></entry>
204	    <entry></entry>
205	  </row>
206	  <row>
207	    <entry>V4L2_DV_BT_656_1120</entry>
208	    <entry>0</entry>
209	    <entry>BT.656/1120 timings</entry>
210	  </row>
211	</tbody>
212      </tgroup>
213    </table>
214  </refsect1>
215  <refsect1>
216    &return-value;
217  </refsect1>
218</refentry>
219