Hello Mauro,

On 17/12/2015 13:55, Mauro Carvalho Chehab wrote:

> Mason wrote:
> 
>> I have a TechnoTrend TT-TVStick CT2-4400v2 USB tuner, as described here:
>> http://linuxtv.org/wiki/index.php/TechnoTrend_TT-TVStick_CT2-4400
>>
>> According to the article, the device is supported since kernel 3.19
>> and indeed, if I use a 4.1 kernel, I can pick CONFIG_DVB_USB_DVBSKY
>> and everything seems to work.
>>
>> Unfortunately (for me), I've been asked to make this driver work on
>> an ancient 3.4 kernel.
>>
>> The linuxtv article mentions:
>>
>> "Drivers are included in kernel 3.17 (for version 1) and 3.19 (for version 2).
>> They can be built with media_build for older kernels."
>> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>
>> This seems to imply that I can use the media_build framework to
>> automatically (??) back-port a 3.19 driver to a 3.4 kernel?
> 
> "automatically" is a complex word ;)

If I get it working, I think you can even say "auto-magically" ;-)

>> This sounds too good to be true...
>> How far back can I go?
> 
> The goal is to allow compilation since 2.6.32, but please notice that
> not all drivers will go that far. Basically, when the backport seems too
> complex, we just remove the driver from the list of drivers that are
> compiled for a given legacy version.
> 
> Se the file v4l/versions.txt to double-check if the drivers you need
> have such restrictions. I suspect that, in the specific case of
> DVB_USB_DVBSKY, it should compile.

That is great news.

> That doesn't mean that it was tested there. We don't test those
> backports to check against regressions. We only work, at best
> effort basis, to make them to build. So, use it with your own
> risk. If you find any problems, feel free to send us patches
> fixing it.

My first problem is that compilation fails on the first file ;-)
See attached log.

My steps are:

cd media_build/linux
make tar DIR=/tmp/sandbox/media_tree
make untar
cd ..
make release DIR=/tmp/sandbox/custom-linux-3.4
make

I will investigate and report back.

Regards.