Markus Rechberger wrote: > On 8/9/07, Steven Toth <stoth@xxxxxxxxxxxxx> 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@xxxxxxx> >>> >>> >>> >> 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. > http://mcentral.de/hg/~mrec/v4l-dvb-experimental/file/c0817d73a2a9/linux/drivers/media/video/em28xx/em28xx-video.c > > 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. > > http://mcentral.de/hg/~mrec/v4l-dvb-experimental/file/f9f3e6bdd6fc/linux/drivers/media/video/em28xx/em2880-dvb.c > > Line 471 - 484 if this would go into the dvb core we'd have a callback > for locking the device nodes. > > Your comment about lines 471-484 make sense, but that code is not referenced via a callback (that I can see in the DVB patch) ... which is what I expected to see. To do this cleanly in the dvb-core (or any v4l-core) I suggest requires callbacks into the bridge-frameworks and I didn't see those callbacks clearly defined in either your original patch, or your follow up patches. I was pretty sure I did something similar for the DVB/MpegEncoder shared bus support. Have you seen this? http://linuxtv.org/hg/~stoth/hvr3000/rev/4b846f1d939b Or more importantly this: http://linuxtv.org/hg/~stoth/hvr3000/rev/a619436699cc Can we just re-use that? - Steve _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
