Avoid removing PID filters when using virtual channel tuning

The first step is to improve the error messages. In two places the "UpdateFilters called in wrong tune mode" message has been updated to specify the value of the wrong tune mode.

After these updates, an example of the error message is:

mythbackend: mythbackend[779282]: E HDHRStreamHandler hdhrstreamhandler.cpp:242 (UpdateFilters) HDHRSH[4] (13249773): UpdateFilters called in wrong tune mode, 4

The tune mode was hdhrTuneModeVChannel (= 4), and we know that UpdateFilters was called, but in hdhrstreamhandler.cpp, the only call to it is avoided for Vchan tuning.

108 void HDHRStreamHandler::run(void)
...
140             UpdateFiltersFromStreamData();
141             if (m_tuneMode != hdhrTuneModeVChannel)
142                 UpdateFilters();

Code examination reveals that the offending invocation of UpdateFilters() is in StreamHandler::RemoveAllPIDFilters().

This routine is called unconditionally in

108 void HDHRStreamHandler::run(void)
...
183     LOG(VB_RECORD, LOG_INFO, LOC + "RunTS(): " + "shutdown");
184
185     RemoveAllPIDFilters();

The solution is to condition the call to RemoveAllPIDFilters() in the same way the call to UpdateFilters() was previously conditioned. If we're using Virtual Channel Tuning, then don't bother removing filters which were never created in the first place.

After applying this solution, the UpdateFilters called in wrong tune mode error messages no longer appear in mythbackend.log.

Resolves #905

Checklist

[x] contribution does not duplicate one of our existing pull requests
[x] contribution is in a branch rebased against master
[x] code compiles successfully without errors
[x] code follows the MythTV Coding Standards
[x] commits are logically organised and have good commit messages

MythTV / mythtv

Avoid removing PID filters when using virtual channel tuning #906

Checklist