[linux-dvb] [PATCH] add device node locking possibility to dvbcore

Markus Rechberger mrechberger at gmail.com
Thu Aug 9 18:55:43 CEST 2007

On 8/9/07, Steven Toth <stoth at hauppauge.com> wrote:
> Markus Rechberger wrote:
> > Following patch adds a rather primitive way to temporary lock dvb
> > devicenodes, this can be useful for hybrid devices which use the
> > video4linux framework for the analogue TV part and the dvb framework for
> > digital TV if only one mode can be accessed at a time.
> >
> > Signed-off-by: Markus Rechberger <markus.rechberger at amd.com>
> >
> >
> Call me dumb but I don't understand how this patch helps v4l devices. :)
> Allocation/management of a single card resource doesn't belong inside
> the dvb framework, these answers need to come from the bridge-frameworks
> (via callbacks from dvb-core or the analog equivalent) who are better
> placed to make the decision about hybrid tuners, bus capacity or
> allocation, in use devices.
> As a working example, I added similar support in my older HVR3000 tree
> where two frontends share a single transport bus. The code is old but it
> demonstrates a solution, much the my earlier patches for shared
> DVB/Blackbird boards also.
> I understand how this patch helps the current dvb tree, it stops
> multiple people opening a device but that's it. ... Or, maybe I've just
> missed to point.

Hi Steve,

the bridge framework triggers locking these filehandles.

line 434
this locks the dvb nodes if someone tries to open the v4l devicenode,
it first checks if there's still something active at the DVB side.


Line 471 - 484 if this would go into the dvb core we'd have a callback
for locking the device nodes.


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