Re: [libdc] Problem Setting Feature Values on Multiple Cameras

[Benedict B. <bjb...@gm...>]

I haven't tried controlling multiple FW cameras on the same machine in a
few years, but it was such a nightmare getting them all to work that I
swore never to do it again.  Even then, I kept each camera on its own bus.

I suspect you have far more experience with multi-camera setups than I do,
so these suggestions may not be much help to you, but just in case...  Have
you tried putting two pairs on the onboard bus and only one on the
expansion card?  What about splitting the cameras 3 and 3?  Finally, are
your FW hubs powered?  Placing four cameras on a single FW bus may well tax
the power it is prepared to supply.  A former colleague of mine who did
manage to get three camera working on the same bus complained about his
firewire cards constantly burning out.

If you have any possibility of testing your code on a mac or with the USB
version of the Firefly MV cameras, that might help distinguish driver
problems from bizarre camera restrictions.  Both options seem like they'll
be difficult or impossible with ROS code though.

Good luck,
Benedict

On Thu, Apr 3, 2014 at 12:24 PM, Zac Lizer <zac...@gm...> wrote:

> Description:
> Running 3 pairs of cameras in externally triggered mode, using the strobe
> from the left camera of each pair to trigger the right. In externally
> triggered mode, these cameras don't support auto_exposure, so I'm
> attempting to read the brightness, shutter, and gain values from the left
> camera (which is free-running and as such can auto-expose) and write them
> to the right camera of the pair, using dc1394_feature_get_value and
> dc1394_feature_set_value.
>
> This works when only running one pair on each Firewire bus, but fails when
> running two pairs on a single bus, with these errors.
>
> libdc1394 error: Generic failure: in dc1394_feature_set_value (control.c,
> line 1265): Could not set feature value
>
> libdc1394 error: Generic failure: in dc1394_feature_set_value (control.c,
> line 1262): Could not get feature value
>
> As far as I can tell, this isn't related to bandwidth usage, because
> slowing the read/writes to once every 1s in the 2 pair case still produces
> errors, while read/writing 15 times a second in the one pair case doesn't
> produce any errors.
>
> I'm making the parameter read/write calls immediately after the image read
> poll.
>
> Any insight into what is causing these errors and how to fix them?
>
> Hardware:
> Point Grey Firefly MV cameras
> Point Grey 3 and 5-port 1394b hubs
>
> FireWire (IEEE 1394): LSI Corporation FW643 [TrueFire] PCIe 1394b
> Controller (rev 08)
> FireWire (IEEE 1394): VIA Technologies, Inc. VT6315 Series Firewire
> Controller (rev 01)
>
> Software:
> ROS Hydro camera1394 node and driver
> libdc1394 2.1.7
> Linux kernel version 3.2.0-59-generic
>
> Topology:
> 6 cameras in 3 pairs
> Port and Starboard pairs on expansion card firewire bus
> Center on onboard firewire bus
>
> -Zac Lizer
>
>
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