[mythtv-users] Nova-TD tuning problem in kernels after 3.2.0

[HP-mini]

On Sat, 2016-04-02 at 19:07 +0100, John Veness wrote:
> Hi,
> 
> I'm running Ubuntu 12.04 LTS (precise) with up-to-date MythTV 0.27
> from the mythbuntu ppa. My tuner is a Hauppauge WinTV Nova-TD Stick,
> which is a USB dual DVB-T tuner.
> 
> All works fine with the 3.2.0 kernel, which is the latest "normal"
> kernel for Ubuntu 12.04. However, if I try later kernels, such as are
> available by installing the linux-generic-lts-quantal (3.5.0), -raring
> (3.8.0), -saucy (3.11.0), or linux-generic-lts-trusty (3.13.0)
> packages, I have tuning problems.
> 
> Specifically, if I just upgrade the kernel and do nothing else, only a
> very few recordings work, the rest being zero bytes. If I try
> rescanning after upgrading the kernel, it finds a couple of hundred
> "conflicting" DVB channels (rather than a couple of hundred
> non-conflicting channels if scanning in 3.2.0), and the transport
> frequencies are different to what I see in 3.2.0, and don't seem to
> work.
> 
> So far, I've tried a couple of time (backing up my mythconverg
> database beforehand) and have had to reverse back to 3.2.0 with a
> database restore, as I haven't had time to investigate further in a
> limited time window.
> 
> Has anyone seen this, and got a fix? I imagine it's the sort of thing
> other Nova-TD users might have seen when upgrading from Ubuntu 12.04
> to 12.10 or later versions.
> 
> Note that I haven't actually tried a full Ubuntu upgrade to a later
> version, just tried the kernel upgrade, which I did as a quick and
> easily reversible way of seeing how a full Ubuntu upgrade might
> perform.
> 
> John
> _______________________________________________
What happens if you try re-scanning in 12.04 with your std kernel?

USB tuner sticks (& nova-t-500 PCI ?) do not get power-on resets that
then forces firmware reloading & (reportedly) allows configuration
changes being applied.. I've not found that to be the case with PCI
tuner.
But hard to believe anything has changed in the device firmware.
Could the LNA get disabled with later kernels?

mythtv-setup produces nice verbose tuning output with the right cmd line
options.

Could try "w_scan" (build from source to get latest 2013) to
compare/contrast the differences with alternative kernels.

I use a nova-t-500 (2 USB devices on a PCI card) & has worked fine
during upgrade from 10.04 to 14.04 (mythtv master).
I probably only used scan-existing-transports & manual updating.
Re-scanned (existing transports) a few weeks ago to fix one channel that
was restacked to make room for more dross.