[pvrusb2] "failed to grab control of dtv input (code=-1)"

[Gary Buhrmaster]

On Tue, Jan 10, 2012 at 19:11, Mike Isely <isely at isely.net> wrote:
> ... I can look into serializing this better.

Thanks for looking.  I had been occasionally receiving the
"failed to grab" error for quite some time, very infrequently,
at boot time on my production mythtv system, which
caused the card init on the DVB side to fail.  Even though
I never used the analog side, and AFAIK nothing else
should have tried to open the analog device, I saw what
I thought was a initialization race in the code on the DVB
side (in the code you mentioned above) as it tried to set
the input modes, so I thought I would try to provoke it
by forcing the analog side to open.  I figured a reliable
reproducer was the first step in debugging.  This case
seemed to be a reliable reproducer (I still have no idea
why something would open /dev/videox during init, but
when I added in systemd device unit initialization for all
udev video4linux subsytem (for other v4l devices), I
seemed to increase the frequency of the "failed to grab"
messages so I decided to try to create a reproducer).

If needed I can test with different debugging options,
or can compile (revised) driver code.

Thanks for any work you do.

And thanks for the driver itself!

Gary