Re: [libdc] State of the JuJu?

[David M. <dcm@MIT.EDU>]

On Thu, 2008-10-02 at 14:19 -0400, David J. Schuller wrote:
> Could someone provide a brief statement or summary of the status of
> interoperability of libdc1394 2.0 with the "Juju" Linux kernel driver?
> Is it ready for prime time yet?
> 

Sure, here's the status of juju support:

With one camera, the latest stable libdc1394 should "just work" with the
latest stable kernel using juju.  Keep in mind you must compile
libdc1394 with the "with-juju-dir" flag to ./configure to get juju
support.  If you use Fedora 9, the shipped libdc1394 should work with
the shipped kernel with no custom compilation.

With two or more cameras, you need to assign an iso channel to each
camera explicitly using the libdc1394 API so that they don't try to send
on the same channel.  This is because the juju kernel does not yet
provide iso allocation functions.  There is a patch floating around on
the linux1394 mailing to add these missing features, and it should be
available in the kernel in the next few versions.

Also, there was a recent bug found in the juju kernel that would cause
errors for users using a 64-bit kernel with 32-bit libdc1394.  If this
applies to you, make sure you have the latest kernel and the latest SVN
version of libdc1394.  Pure 64-bit and pure 32-bit environments should
not be affected.  If you are concerned about this let me know and I can
dig around for specific version numbers with the fix.

I believe I've enumerated all the current caveats of juju as it applies
to libdc1394.

Something on my todo list is to make libdc1394 auto-detect the kernel
firewire stack at runtime, so the custom compilation for juju is no
longer necessary.  The newest version of libraw1394 uses this approach.

Let me know if you have any other questions.

-David