[pvrusb2] Failure to compile on FC5 / 2.6.16

[Mike Isely]

Robert:

I got a clean build here using vanilla kernel 2.6.16.1.  So....

I think I might know what is going on here and you're probably not going 
to want to hear it :-(

There are various APIs that have been getting thrashed / changed etc in 
each version of the kernel.  Some changes have been in V4L while others 
have been in the kernel itself.  An out-of-tree driver like this one has 
only a single defense against this - by implementing conditionally 
compiled code that conditions itself on the kernel version against which 
the driver is being compiled.  That works well for vanilla kernels. 
However when a distribution vendor back-ports changes between different 
versions of the kernel then you can get problems where such a change might 
subtlely change an API and then compilation breaks.  I think that might be 
the case here.

I am pretty sure that the msp_matrix structure in fact did recently move 
around a bit in the 2.6.16 timeframe.

I can't get into the business of identifying distro-specific versions and 
modifying the driver to adapt to stuff like that.  I'm not a Fedora user 
so there's no way I can test this sort of thing.  Also if I were to try to 
support Fedora in this way, then where does it stop?  The burden of having 
to test compile against each possible kernel variant can be overwhelming. 
I have a hard enough time just testing compiling against 4-6 kernel 
versions for each snapshot - and if you look at the change history you'll 
see I've failed in that regard multiple times...

Is there any chance you can switch to a vanilla kernel from kernel.org? 
Failing that you might be able to take some stabs at various other FC 
derived kernels.  You could also just try to edit the driver sources and 
if you want to send me a patch I'll look at it - but I can't promise I'll 
include it if it might be hazardous to the vanilla kernels.  Also in any 
case even if I apply such a patch I can't support it or guarantee that it 
will continue to build correctly in the future.

I'm not trying to be a pain; it's just that there's a limit to how many 
kernel variants I can juggle here and still have time left to actually 
improve the driver :-(

   -Mike


On Fri, 7 Apr 2006, Robert Kulagowski wrote:

> I think I read everything on the web page and didn't see any mention of
> this issue:
>
> $ pwd
> /home/mythtv/pvrusb2-mci-20060329/driver
> $  make
> make INSTALL_MOD_DIR=pvrusb2 -C /lib/modules/2.6.16-1.2080_FC5smp/source
> M=/home/mythtv/pvrusb2-mci-20060329/driver CONFIG_VIDEO_PVRUSB2=m modules
> make[1]: Entering directory `/usr/src/kernels/2.6.16-1.2080_FC5-smp-i686'
>   CC [M]  /home/mythtv/pvrusb2-mci-20060329/driver/pvrusb2-audio.o
> In file included from
> /home/mythtv/pvrusb2-mci-20060329/driver/pvrusb2-audio.c:36:
> include/media/v4l2-common.h:124: error: redefinition of âstruct msp_matrixâ
> make[2]: *** [/home/mythtv/pvrusb2-mci-20060329/driver/pvrusb2-audio.o]
> Error 1
> make[1]: *** [_module_/home/mythtv/pvrusb2-mci-20060329/driver] Error 2
> make[1]: Leaving directory `/usr/src/kernels/2.6.16-1.2080_FC5-smp-i686'
> make: *** [modules] Error 2
>
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