[pvrusb2] My tuners occasionally get stuck

[Gary Buhrmaster]

On Wed, Mar 21, 2012 at 06:12, Jan Ceuleers <jan.ceuleers at gmail.com> wrote:
> Hi there.
....
> Does anyone have any idea as to how to begin debugging this?

<conjecture>

Almost certainly a kernel usb issue.  The 1900s and the
APC device are likely victims, not the cause.  These types
of bug reports (the 'clear tt' ones) with usb devices have a
tendency to reoccur on some irregular basis as the usb
subsystem in the kernel gets improved.  Usually the
problem is patched in the next kernel rev (because others
have reported it), although sometimes you have to do the
git bisect to find the patch that was "special" to get it fixed.

I would look to the forums that discuss Ubuntu for
assistance to find a recommended kernel that has
been reported to work with your hardware.

It seems to be an unfortunate reality that the hauppauge
devices can end up getting hung if you poke enough
bad usb data at them long enough that requires a power
cycle to reset (this happened to me on windows years
ago too, and I presume it is still true today).  My guess
is that after you reboot your linux system, the kernel is
not able to detect or enumerate the hauppauge devices
correctly (I have seen that on my current linux system
after certain power "opportunities" that PG&E have provided),
so that the driver is unable to reset a device it does not have
access to.  It might be useful to capture the boot messages
during a "normal" boot and a boot in which the devices
are not started, to see what messages the driver
emits.  It is always possible that some initialization code(s)
could be improved.  But the root cause is probably still
the kernel usb subsystem.  Find a kernel that works, and
you are not likely to see the problems in the first place.

</conjecture>

Gary