Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 61 insertions, 0 deletions

diff --git a/Documentation/media/dvb-drivers/udev.rst b/Documentation/media/dvb-drivers/udev.rst
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+UDEV rules for DVB
+==================
+
+.. note::
+
+   #) This documentation is outdated. Udev on modern distributions auto-detect
+      the DVB devices.
+
+   #) **TODO:** change this document to explain how to make DVB devices
+      persistent, as, when a machine has multiple devices, they may be detected
+      on different orders, which could cause apps that relies on the device
+      numbers to fail.
+
+The DVB subsystem currently registers to the sysfs subsystem using the
+"class_simple" interface.
+
+This means that only the basic information like module loading parameters
+are presented through sysfs. Other things that might be interesting are
+currently **not** available.
+
+Nevertheless it's now possible to add proper udev rules so that the
+DVB device nodes are created automatically.
+
+We assume that you have udev already up and running and that have been
+creating the DVB device nodes manually up to now due to the missing sysfs
+support.
+
+0. Don't forget to disable your current method of creating the
+device nodes manually.
+
+1. Unfortunately, you'll need a helper script to transform the kernel
+sysfs device name into the well known dvb adapter / device naming scheme.
+The script should be called "dvb.sh" and should be placed into a script
+dir where udev can execute it, most likely /etc/udev/scripts/
+
+So, create a new file /etc/udev/scripts/dvb.sh and add the following:
+
+.. code-block:: none
+
+	#!/bin/sh
+	/bin/echo $1 | /bin/sed -e 's,dvb\([0-9]\)\.\([^0-9]*\)\([0-9]\),dvb/adapter\1/\2\3,'
+
+Don't forget to make the script executable with "chmod".
+
+1. You need to create a proper udev rule that will create the device nodes
+like you know them. All real distributions out there scan the /etc/udev/rules.d
+directory for rule files. The main udev configuration file /etc/udev/udev.conf
+will tell you the directory where the rules are, most likely it's /etc/udev/rules.d/
+
+Create a new rule file in that directory called "dvb.rule" and add the following line:
+
+.. code-block:: none
+
+	KERNEL="dvb*", PROGRAM="/etc/udev/scripts/dvb.sh %k", NAME="%c"
+
+If you want more control over the device nodes (for example a special group membership)
+have a look at "man udev".
+
+For every device that registers to the sysfs subsystem with a "dvb" prefix,
+the helper script /etc/udev/scripts/dvb.sh is invoked, which will then
+create the proper device node in your /dev/ directory.