linux/Documentation/DocBook/media/v4l/gen-errors.xml

<title>Generic Error Codes</title>

<table frame="none" pgwide="1" id="gen-errors">
  <title>Generic error codes</title>
  <tgroup cols="2">
    &cs-str;
    <tbody valign="top">
	<!-- Keep it ordered alphabetically -->
      <row>
	<entry>EBADF</entry>
	<entry><parameter>fd</parameter> is not a valid open file descriptor.</entry>
      </row>
      <row>
	<entry>EBUSY</entry>
	<entry>The ioctl can't be handled because the device is busy. This is
	       typically return while device is streaming, and an ioctl tried to
	       change something that would affect the stream, or would require the
	       usage of a hardware resource that was already allocated. The ioctl
	       must not be retried without performing another action to fix the
	       problem first (typically: stop the stream before retrying).</entry>
      </row>
      <row>
	<entry>EFAULT</entry>
	<entry><parameter>fd</parameter> is not a valid open file descriptor.</entry>
      </row>
      <row>
	<entry>EINVAL</entry>
	<entry>One or more of the ioctl parameters are invalid. This is a widely
	       used error code. See the individual ioctl requests for actual causes.</entry>
      </row>
      <row>
	<entry>EINVAL or ENOTTY</entry>
	<entry>The ioctl is not supported by the driver, actually meaning that
	       the required functionality is not available, or the file
	       descriptor is not for a media device.</entry>
      </row>
      <row>
        <entry>ENODEV</entry>
	<entry>Device not found or was removed.</entry>
      </row>
      <row>
	<entry>ENOMEM</entry>
	<entry>There's not enough memory to handle the desired operation.</entry>
      </row>
      <row>
	<entry>ENOSPC</entry>
	<entry>On USB devices, the stream ioctl's can return this error, meaning
	       that this request would overcommit the usb bandwidth reserved
	       for periodic transfers (up to 80% of the USB bandwidth).</entry>
      </row>
    </tbody>
  </tgroup>
</table>

<para>Note 1: ioctls may return other error codes. Since errors may have side
effects such as a driver reset, applications should abort on unexpected errors.
</para>

<para>Note 2: Request-specific error codes are listed in the individual
requests descriptions.</para>