[mythtv-users] winTV-dualHD in 32on64 config

[Ian Campbell]

I have a 32-bit mythtv 0.28 install (Debian based, using dmo mythtv
packages) with a winTV-dualHD USB dongle which works great (well, the
first tuner does, the second is not yet supported).

The system has 6G of RAM and runs Debian's 4.9 kernel from Stretch (PAE
flavour so it has access to all 6G) however I was considering a cross
grade to 64-bit and as a first step decided to run the existing 32-bit
userspace on a 64-bit kernel. I was also hoping this might help
mitigate some db performance issues I'd been seeing.

In the 32 on 64 configuration the winTV-dualHD fails to tune, I
rebooted between the two kernels several times and it seems to
consistently work with the PAE kernel and fail with the amd64 kernel.

Has anyone come across this before? I have a vague memory of historical
issues with v4l and compat ioctls (i.e. the translation applied to
ioctls made by 32-bit applications on a 64-bit kernel) but I think that
was a long time ago and might be fixed by now. Does anyone know if this
configuration still has issues? I appreciate it is quite a rare one so
perhaps noone knows.

The system also has some PVR 500 non-HD PCI tuners in it, which seem to
work fine with both kernels, so maybe this is just a driver specific
issue, or is somehow specific to HD tuners.

Alternatively does anyone have experience with the winTV-dualHD in a
fully 64-bit mythtv 0.28 configuration? If it works then that might
make me more confident about proceeding with a (possibly partial)
cross-grade of the userspace.

Ian.