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

1	<title>Generic Error Codes</title>
2	
3	<table frame="none" pgwide="1" id="gen-errors">
4	  <title>Generic error codes</title>
5	  <tgroup cols="2">
6	    &cs-str;
7	    <tbody valign="top">
8		<!-- Keep it ordered alphabetically -->
9	      <row>
10		<entry>EAGAIN (aka EWOULDBLOCK)</entry>
11		<entry>The ioctl can't be handled because the device is in state where
12		       it can't perform it. This could happen for example in case where
13		       device is sleeping and ioctl is performed to query statistics.
14		       It is also returned when the ioctl would need to wait
15		       for an event, but the device was opened in non-blocking mode.
16		</entry>
17	      </row>
18	      <row>
19		<entry>EBADF</entry>
20		<entry>The file descriptor is not a valid.</entry>
21	      </row>
22	      <row>
23		<entry>EBUSY</entry>
24		<entry>The ioctl can't be handled because the device is busy. This is
25		       typically return while device is streaming, and an ioctl tried to
26		       change something that would affect the stream, or would require the
27		       usage of a hardware resource that was already allocated. The ioctl
28		       must not be retried without performing another action to fix the
29		       problem first (typically: stop the stream before retrying).</entry>
30	      </row>
31	      <row>
32		<entry>EFAULT</entry>
33		<entry>There was a failure while copying data from/to userspace,
34		       probably caused by an invalid pointer reference.</entry>
35	      </row>
36	      <row>
37		<entry>EINVAL</entry>
38		<entry>One or more of the ioctl parameters are invalid or out of the
39		       allowed range. This is a widely used error code. See the individual
40		       ioctl requests for specific causes.</entry>
41	      </row>
42	      <row>
43	        <entry>ENODEV</entry>
44		<entry>Device not found or was removed.</entry>
45	      </row>
46	      <row>
47		<entry>ENOMEM</entry>
48		<entry>There's not enough memory to handle the desired operation.</entry>
49	      </row>
50	      <row>
51		<entry>ENOTTY</entry>
52		<entry>The ioctl is not supported by the driver, actually meaning that
53		       the required functionality is not available, or the file
54		       descriptor is not for a media device.</entry>
55	      </row>
56	      <row>
57		<entry>ENOSPC</entry>
58		<entry>On USB devices, the stream ioctl's can return this error, meaning
59		       that this request would overcommit the usb bandwidth reserved
60		       for periodic transfers (up to 80% of the USB bandwidth).</entry>
61	      </row>
62	      <row>
63		<entry>EPERM</entry>
64		<entry>Permission denied. Can be returned if the device needs write
65			permission, or some special capabilities is needed
66			(e. g. root)</entry>
67	      </row>
68	    </tbody>
69	  </tgroup>
70	</table>
71	
72	<para>Note 1: ioctls may return other error codes. Since errors may have side
73	effects such as a driver reset, applications should abort on unexpected errors.
74	</para>
75	
76	<para>Note 2: Request-specific error codes are listed in the individual
77	requests descriptions.</para>
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