On 12/04/2013 02:17 AM, Laurent Pinchart wrote: > Hi Hans, > > On Tuesday 03 December 2013 10:56:07 Hans Verkuil wrote: >> On 11/29/13 19:21, Laurent Pinchart wrote: >>> On Friday 29 November 2013 10:58:42 Hans Verkuil wrote: >>>> From: Hans Verkuil <hans.verkuil@xxxxxxxxx> >>>> >>>> In order to implement vb2 DVB or ALSA support you need to be able to >>>> start a kernel thread that queues and dequeues buffers, calling a >>>> callback function for every captured/displayed buffer. This patch adds >>>> support for that. >>>> >>>> It's based on drivers/media/v4l2-core/videobuf-dvb.c, but with all the >>>> DVB specific stuff stripped out, thus making it much more generic. >>> >>> Do you see any use for this outside of videobuf2-dvb ? If not I wonder >>> whether the code shouldn't be moved there. The sync objects framework >>> being developed for KMS will in my opinion cover the other use cases, and >>> I'd like to discourage non-DVB drivers to use vb2 threads in the >>> meantime. >> >> I'm using it for ALSA drivers which, at least in my case, require almost >> identical functionality as that needed by DVB. > > You're using videobuf2 for audio ? For this particular board the audio DMA is just another DMA channel. Handling audio DMA is identical to video DMA. Why reinvent the wheel? The board I developed this for has somewhat peculiar audio handling (sorry, it's an internal product and I can't go into details), but I'll do the same exercise for another board that I can open source and there audio handling is standard. I want to see if I can use that to develop a videobuf2-alsa.c module that takes care of most of the alsa complexity. I don't know yet how that will work out, I'll have to experiment a bit. > >> But regardless of that, I really don't like the way it was done in the old >> videobuf framework, mixing low-level videobuf calls/data structure accesses >> with DVB code. That should be separate. >> >> The vb2 core framework should provide the low-level functionality that is >> needed by the videobuf2-dvb to build on. > > Right, but I want to make sure that drivers will not start using this > directly. What sort of use-cases were you thinking of, other than DVB and ALSA? I don't off-hand see one. > It should be an internal videobuf2 API. I happily add comments to the source and header mentioning that it is for core use only and that for any other uses the mailinglist should be contacted, but I really don't want to mix core vb2 code with DVB code. That should remain separate. Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
