doc_rst: rename the media Sphinx suff to Documentation/media

The name of the subsystem is "media", and not "linux_tv". Also,
as we plan to add other stuff there in the future, let's
rename also the media uAPI book to media_uapi, to make it
clearer.

No functional changes.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/media/uapi/gen-errors.rst

@@ -0,0 +1,101 @@
+.. -*- coding: utf-8; mode: rst -*-
+
+.. _gen_errors:
+
+*******************
+Generic Error Codes
+*******************
+
+
+.. _gen-errors:
+
+.. flat-table:: Generic error codes
+    :header-rows:  0
+    :stub-columns: 0
+    :widths: 1 16
+
+
+    -  .. row 1
+
+       -  ``EAGAIN`` (aka ``EWOULDBLOCK``)
+
+       -  The ioctl can't be handled because the device is in state where it
+	  can't perform it. This could happen for example in case where
+	  device is sleeping and ioctl is performed to query statistics. It
+	  is also returned when the ioctl would need to wait for an event,
+	  but the device was opened in non-blocking mode.
+
+    -  .. row 2
+
+       -  ``EBADF``
+
+       -  The file descriptor is not a valid.
+
+    -  .. row 3
+
+       -  ``EBUSY``
+
+       -  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).
+
+    -  .. row 4
+
+       -  ``EFAULT``
+
+       -  There was a failure while copying data from/to userspace, probably
+	  caused by an invalid pointer reference.
+
+    -  .. row 5
+
+       -  ``EINVAL``
+
+       -  One or more of the ioctl parameters are invalid or out of the
+	  allowed range. This is a widely used error code. See the
+	  individual ioctl requests for specific causes.
+
+    -  .. row 6
+
+       -  ``ENODEV``
+
+       -  Device not found or was removed.
+
+    -  .. row 7
+
+       -  ``ENOMEM``
+
+       -  There's not enough memory to handle the desired operation.
+
+    -  .. row 8
+
+       -  ``ENOTTY``
+
+       -  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.
+
+    -  .. row 9
+
+       -  ``ENOSPC``
+
+       -  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).
+
+    -  .. row 10
+
+       -  ``EPERM``
+
+       -  Permission denied. Can be returned if the device needs write
+	  permission, or some special capabilities is needed (e. g. root)
+
+
+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.
+
+Note 2: Request-specific error codes are listed in the individual
+requests descriptions.