How to Obtain, Build and Install V4L-DVB Device Drivers

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Revision as of 23:15, 8 October 2005 by Mkrufky (talk | contribs) (new tree-merge instructions)
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An outline of the procedure used to successfully build the drivers in video4linux CVS. If you want the drivers already working properly in the kernel these are not the instructions to follow.

I did this on linux-2.6.12-gentoo and tested the lgdt3302 driver for a card I own. It should be applicable to the other drivers in CVS as well. CVS is usually only going to work on recent linux kernels.

1) Configure your kernel. If multimedia drivers in addition to those specified here are selected, you may end up loading an old copy of a module compiled by the kernel rather than the new version just compiled from CVS.

Run:

   make menuconfig

in the Linux source directory and set things like this:

   Device Driver --->
       Multimedia Devices --->
           <M> Video for Linux
               Digital Video Broadcasting Devices --->
                   [*] DVB for Linux
                   <M> DVB Core

If you don't need any of the digital drivers do not select DVB Core.

                   < > DVB Core

No other drivers or options should be selected under Multimedia Devices ---> or any lower level.

2) Follow your normal procedure for recompiling and installing your kernel if you changed anything with menuconfig in step 1.

3a) Check out v4l-kernel CVS files following the instructions at linuxtv.org [Repeated here].

   cvs -d :pserver:anonymous@cvs.linuxtv.org:/cvs/video4linux login
   cvs -d :pserver:anonymous@cvs.linuxtv.org:/cvs/video4linux co v4l-kernel

3b) (optional) If you would like to include latest DVB frontend module support within your build, check out dvb-kernel CVS files following the instructions at linuxtv.org [Repeated here]. If you choose to complete this step, you will also have to complete step 4b as well.

   cvs -d :pserver:anonymous@cvs.linuxtv.org:/cvs/linuxtv login
   cvs -z3 -d :pserver:anonymous@cvs.linuxtv.org:/cvs/linuxtv co -P dvb-kernel

3c) (optional) You can later update your sources by running:

   cvs -z3 up -dP

4a) Change into the v4l-kernel directory:

   cd v4l-kernel

4b) If you followed step 3b above for DVB frontends to be built, then you will need to patch the Makefile and symlink the frontend code using the merge-trees script. The script does everything you need in order to merge the required frontend code into the v4l tree. It assumes that both cvs trees are located in the same directory level, and that it is being called from within /v4l-kernel:

   make merge-trees

5) Compile the modules:

   make

6a) As root, after compiling the modules you can make them available to the OS with:

   make install

6b) (optional) If, for any reason, the above doesn't work with your setup, there is another option:

   make v4l_install

7) Now you can install the driver you need into the OS. Each driver from within CVS has been built.

My particular driver needs:

   modprobe -v cx8800
   modprobe -v cx88-dvb

The -v option is handy for checking where the driver module actually was found. If your startup scripts are configured correctly, these modules can be set up to load automatically on system boot.

8) One of the most common problem with CVS build is missing dvb headers. Here is example of gcc output:

In file included from /usr/src/cvs/video4linux/cx88.h:33, 
                from /usr/src/cvs/video4linux/cx88-video.c:37: 
/usr/src/cvs/video4linux/media/video-buf-dvb.h:5:20: dvbdev.h: No such file or 
directory 
/usr/src/cvs/video4linux/media/video-buf-dvb.h:6:20: dmxdev.h: No such file or 
directory 
/usr/src/cvs/video4linux/media/video-buf-dvb.h:7:23: dvb_demux.h: No such file 
or directory 
/usr/src/cvs/video4linux/media/video-buf-dvb.h:8:21: dvb_net.h: No such file or 
directory 
/usr/src/cvs/video4linux/media/video-buf-dvb.h:9:26: dvb_frontend.h: No such 
file or directory  
In file included from /usr/src/cvs/video4linux/cx88.h:33, 
                from /usr/src/cvs/video4linux/cx88-video.c:37: 
/usr/src/cvs/video4linux/media/video-buf-dvb.h:28: error: field `demux' has 
incomplete type 
/usr/src/cvs/video4linux/media/video-buf-dvb.h:29: error: field `dmxdev' has 
incomplete type 
/usr/src/cvs/video4linux/media/video-buf-dvb.h:30: error: field `fe_hw' has 
incomplete type 
/usr/src/cvs/video4linux/media/video-buf-dvb.h:31: error: field `fe_mem' has 
incomplete type 
/usr/src/cvs/video4linux/media/video-buf-dvb.h:32: error: field `net' has 
incomplete type 
make[2]: *** [/usr/src/cvs/video4linux/cx88-video.o] Error 1 
make[1]: *** [_module_/usr/src/cvs/video4linux] Error 2 
make[1]: Leaving directory `/usr/src/linux-headers-2.6.11-1-686' 

The problem is in missing files in some kernel sources installation (For example on Fedora or Ubuntu). These files are present in original kernel sources and are stripped somehow in those distributions. (These header files are located in drivers/media/dvb/dvb-core, not include/linux/dvb) To fix this problem you can download original kernel sources or kernel source packet and manually extract the missing files gcc warns you about. You can place them to directory with other kernel headers or directly into v4l directory. An easier solution is to grab these header files from dvb-kernel cvs, using the tree-merging scripts, outlined above.