How to Obtain, Build and Install V4L-DVB Device Drivers
The LinuxTV project hosts the latest set of Linux kernel driver modules for V4L-DVB devices. This page contains information to help an "end user" install these device drivers in a GNU/Linux system..
- 1 Software Requirements
- 2 Retrieving and Building/Compiling, and Installing the Latest V4L-DVB Source Code
- 3 First Use: Out with the Old, In with the New
- 4 Some Further Documentation
The LinuxTV V4L-DVB drivers will work only in conjunction with relatively modern 2.6 kernels; specifically,
Additional Software Requrirements
In order to be able to build the V4L-DVB kernel driver modules, you will need:
- kernel-source or kernel-headers
- (OpenSuSE and fedora only) kernel-devel
If these packages are not currently installed on your system, you should do so now.
Retrieving and Building/Compiling, and Installing the Latest V4L-DVB Source Code
There are a couple of different methods by which you can obtain, build and install the latest source code. Regardless of which route you take, all are performed from the command line within a console. The "basic" method is likely appropriate for most end users, though, in some cases, some users will have to use the slightly more manually intensive approach. Again, before proceeding, make sure you have installed all the prerequisite software listed above.
Basic Method using the "build.sh" script
git clone git://linuxtv.org/media_build.git cd media_build ./build.sh
These commands will download the newest tarball of the source code from linuxtv.org, apply the backport patches to it and then build/compile the source. If the compilation process completed successfully, you can now skip ahead to the Installation of the modules section below.
If you experience any errors in the build process, or if wish to modify a particular driver before compilation, then try following the manual steps instead.
More Manual Approach to Acquiring and Building/Compiling the Modules
This more manual approach is effectively for all intense purposes, really just the same as the "basic" method outlined above. The major difference being this more manual approach allows you the chance to tailor the source code or the "make"/build process as required in your particular situation. Without further ado, perform the following commands:
git clone git://linuxtv.org/media_build.git cd media_build/linux make tar DIR=<some dir with media -git tree> make untar cd ..
If you need to make any sort of change or modification to the source code, now is the time.
Next, build/compile the modules from the source code with the command:
This will create a /v4l directory within which the completed *.ko module files will be written. Generally, this step will tend to take a while to complete; being dependent upon both the number of modules being built and your system's processing power.
The build progress can be observed via the console output. Some drivers included within the snapshot may have their own requirements in regards to the kernel that you must be running in order for the module to be built; such cases can be found listed at the beginning of the build output.
The entire build process should complete without error. If any errors are encountered, the compilation will be halted and, at this point, you should not attempt to proceed any further (unless you really, really enjoy experiencing the outcome of a preordained failure). Errors that prevent building a particular V4L-DVB snapshot do indeed surface from time to time, but these are usually corrected quickly upon notification from an end user submitted bug report, or upon detection from the daily automated build tests (see note below).
If you do run into any problems during the build step, you should:
- first, see whether the issue is already known or not -- consult the results of the daily automated build tests (see note above)
- if it appears that this is a new issue, please inform the developers of the bug via the LMML (preferred) or thorough one of the irc.freenode.net irc channels (#v4l or #linuxtv or #dvb).
- you may also wish to consult any errata that might be found on this article's talk page
In general, if the source builds correctly, it is likely that the drivers will work, though this is not a guarantee.
Installing the Modules
The next step is to install the kernel driver modules by executing:
sudo make install
The command above will prompt you for your root password, and will then copy the *.ko module files you built in the above step into the /lib/modules/[kernel version]/kernel/drivers/media directories.
First Use: Out with the Old, In with the New
Before trying to use the device with your newly installed driver set, you should remove from system memory any older versions of related modules that may have been loaded by the running kernel; otherwise, you will likely run into various fatal mismatch errors -- typified by an "unknown symbol" or "unknown parameter" -- as a result of your system trying to work from a mixture of old and new modules.
To achieve a clean slate state, you could either:
1. Reboot: Perhaps the most straightforward thing to do at this point, particularly for Linux newbies, is to just restart your system; the reboot will, obviously, clear out the old modules loaded into memory and, as an added bonus, create a fresh running environment under which the new modules should have been automagically loaded into system memory.
Or, on the other hand,
2. Take care of business yourself: More experienced users might prefer to use more eloquent approaches. For example, using
sudo make unload
will essentially (and similar as to manually using "rmmod" commands) remove all older modules for the device that might be currently loaded in memory by the running kernel. After which, one can then load, from the newly installed device driver set, the appropriate modules for the device using relevant
Regardless of which approach you take to remove the old modules and to insert the new ones, the end result should be the same. In addition, upon future starts of your system, your device should "automagically" be detected and will have the appropriate driver modules loaded into memory.
If the Modules load correctly:
Provided that the modules were loaded correctly into system memory:
1. They should be listed in /proc/modules: you can use either
cat /proc/modules or, even better,
lsmod to see this content.
Which modules should you be looking for? Well, the answer to that question depends entirely upon the chipsets used by your device -- see the relevant wiki article for your device for a listing of such components and required drivers (or search the web if such information does not exist. Note: Please add any information missing from the wiki!)
2. They should provide some indication within your system log: you can consult the output from the "
dmesg" command or directly review your system log file (typically housed within the /var/log directory) for indication that they have been successfully loaded and that the device is now correctly configured for operation. Examples of successful module loads are provided by users under the "Sample kernel output" section in many device articles witin the wiki.
3. The device manager udev will "automagically" create appropriate device nodes on /dev:
(a) For a DVB device, you should now have a non-empty /dev/dvb directory. You can check on whether this is true for you with the following command:
ls -l /dev/dvb/
(alternatively, you can browse your directory structure with the graphical file manager of your choice). If you have a single DVB device installed in your system, then the output of the above command should reveal that /dev/dvb/ is populated by adapter0. Digging further,
ls -l /dev/dvb/adapter0
reveals the character devices associated with adapter0 for which the drivers have control. If you have more then one DVB device, you can see the same for all with
ls -l /dev/dvb/adapter*
(b) For a V4L device, you should now have a non-empty /dev/v4l directory. You can check on whether this is true for you with the following command:
ls -l /dev/v4l
ls -l /dev/v4l/by-path
reveals the symbolic links to the character devices associated with your V4L adapter for which the drivers have control. The most typical of which is /dev/video0. If you have more then one V4L device, you can see the same for all with
ls -l /dev/video*
If the Modules did not load correctly or the device is still not configured correctly for use:
There could be several reasons why you may have encountered a module loading error or, absent such an error, why the device is still not configured correctly for use, even after having correctly followed the steps from the above procedure. If either of these cases applies, the very first thing you should do is check whether your device is actually supported by the driver (see the very first note at the top of this page). Next, provided your device is supposed to be supported, check within your system log/dmesg for any messages that may give indication as to the problem. The following points address a few common trouble spots:
Module Load Order Can Matter
- in cases where loading more then one module is necessary, the order in which you load the modules can matter!
Sometimes Automagic just isn't Automagic
- If a module was, for whatever reason, not loaded, you can try manually loading it with the appropriate modprobe command.
- if you tried the second method ("make unload" followed by an appropriate modprobe command) but encountered errors in relation to unresolved symbols, e.g. using the saa7134 module as an example:
sudo modprobe saa7134 FATAL: Error inserting saa7134 (/lib/modules/[your kernel version]/kernel/drivers/media/video/saa7134/saa7134.ko):\ Unknown symbol in module, or unknown parameter (see dmesg)
please try a system reboot before filing an error report. Irregardless of what caused the unresolved symbols errors, usually, after performing the reboot, you will find that the install was actually successful and the drivers will work as intended.
- Special case: If your system uses compressed kernel modules, after running the "make install" command of the V4L-DVB installation process, you could end up with a mixture of new modules (*.ko) and their older compressed version (*.ko.gz) installed. If the system attempts to concurrently load both sets into memory, you are bound to run into modprobe insertion errors (eg. unknown symbol or unknown parameter). All conflicting *.ko.gz files must be removed. The following command line can help you locate these conflicting files in all your installed kernels:
for file in `find /lib/modules -name "*.ko"`; do if [[ -e $file.gz ]]; then echo "$file.gz should be removed"; fi; done
Usually all conflicting module files resulting of v4l-dvb installation will be located in:
/lib/modules/[your kernel version]/kernel/drivers/media
Once the conflicting *.ko.gz have been moved elsewhere or renamed (to *.ko.gz.disabled for example), use the v4l-dvb reload command and, to be safe, also add a "depmod" step in order to rebuild modules dependencies):
make reload depmod -a
Your new modules should now be loaded correctly.
A Note on Firmware
- You have all the modules active (listed in lsmod) but device nodes are nowhere to be found: The problem may be as simple as the firmware for the device not being loaded; some devices also require a firmware, which is uploaded from the host PC to the device, in order to operate.
In some cases, when the device is correctly recognized, the associated drivers provide information as to which firmware file is required -- look in the system log output. For example, for many TechnoTrend & Hauppauge (and other similar "premium" cards), if the dvb-ttpci firmware is not available you will observe an error such as:
dvb-ttpci: could not load firmware, file not found: dvb-ttpci-01.fw dvb-ttpci: usually this should be in /usr/lib/hotplug/firmware or /lib/firmware dvb-ttpci: and can be downloaded from http://www.linuxtv.org/download/dvb/firmware/
Resolving that missing firmware issue should then result in proper detection and configuration of your device. In other cases, obtaining the correct firmware is not so straightforward a task. The very first thing you need to know is what device you're using; see "Determining the Device's Identity". Once you have established which particular device you are in possession of, you can then move on to obtaining the correct firmware. In addition, information in wiki articles (eg. such as DVB-T USB Devices) will cite the appropriate firmware required. If you're still at a loss, a Google search may shed light on what file you need. Note, however, that not all supported devices have easily available firmware (eg. Hauppauge HVR 1100 & 1300). Firmware for such cards could be loaded via temporary installation in a Mirosoft Windows System with the manufacturer-supplied drivers.
In any regard, once you find and obtain the necessary firmware for your device, copy it into the appropriate directory; the directory location depends upon that used by your distro, but typically it is:
Consult resources for your distro if its preferred location is somewhere otherwise.
Some Further Documentation
- See Testing your DVB device for instructions on testing your newly installed DVB device