Re: sniff firewire pass though

Carl Karsten wrote:
> OT, i think I remember of a firewire driver list, but can't find it.

https://ieee1394.wiki.kernel.org/index.php/Contact

> I am hoping I can put a linux box in between a windows box and a
> firewire device (Canopus Twinpact100 vga scan converter.)
> 
> There is a windows app that will send commands to the twinpact.  I
> want to be able to send those commands from a linux app (dvswitch).

If you have an OHCI-1394 controller in the Linux box, then you can
merely capture isochronous streams, i.e. the video.  This is because
streams are addressed to "channels" which may have 0..n listeners.

An OHCI-1394 controller won't capture asynchronous transactions that go
forth between two other nodes.  This is because asynchronous
transactions are addressed to "node IDs" _and_ the OHCI-1394 spec
explicitly forbids to receive asynchronous packets that are destined to
a different node ID than the local one.  The control commands that you
are keen on are transported by asynchronous transactions.

The physical topology (order of Windows box, camera, Linux box on the
bus) does not matter WRT the ability or disability to receive
isochronous and asynchronous traffic.

But you can put your plan into action with a PCILynx controller.  These
ones were designed before OHCI-1394 came out, and they implement a
promiscuous mode.  To make use of that, you need the bus analyzer
software "Nosy", written by Kristian Høgsberg.  It consists of a kernel
driver and a userspace utility.

https://ieee1394.wiki.kernel.org/index.php/Out-of-tree_Kernel_Drivers

Known PCILynx based controllers are
  - Apple PowerMac G3 blue & white (onboard controller)
  - IOI IOI-1394TT (PCI card)
  - Newer Technology FireWire 2 Go (CardBus card)
  - Unibrain FireBoard 400 (PCI card)

> In case you are interested, the commands are:
> source: twin pact has 3 inputs, vga is one of them.
> overscan - use the full 720x480 or exclude the safe zone.
> zoom/pan - a 1024x768 is down sampled to ntsc, or it can zoom in on a
> region so that pixels are kept 1:1.

You could ask Grass Valley for a spec sheet.
-- 
Stefan Richter
-=====-==-=- -=-- ===--
http://arcgraph.de/sr/

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