libv4l2 and the Hauppauge HVR1600 (cx18 driver) not working well together

[Simon Farnsworth <simon.farnsworth@onelan.com>]

Hello,

I'm in the process of reworking Xine's input_v4l to use libv4l2, so that
  it gets the benefit of all the work done on modern cards and webcams,
and I've hit a stumbling block.

I have a Hauppauge HVR1600 for NTSC and ATSC support, and it appears to
simply not work with libv4l2, due to lack of mmap support. My code works
adequately (modulo a nice pile of bugs) with a HVR1110r3, so it appears
to be driver level.

Which is the better route to handling this; adding code to input_v4l to
use libv4lconvert when mmap isn't available, or converting the cx18
driver to use mmap?

If it's a case of converting the cx18 driver, how would I go about doing
that? I have no experience of the driver, so I'm not sure what I'd have
to do - noting that if I break the existing read() support, other users
will get upset.

-- 
Advice appreciated,

Simon Farnsworth