On 04/22/15 20:31, Mauro Carvalho Chehab wrote: > This is the first draft for the Linux Media Summit Report. > > Please note that the items 3 to 5 are not in good shape. In special, > nobody took Etherpad notes on item 4.
Item 4 was just me presenting on ongoing projects. As far as I remember there was no discussion and a link to my presentation would be enough. I know I mailed it to you. > > Please review. I'll publish a second (final?) draft after having some > feedback. > > Regards, > Mauro > > - > > Linux Media Summit - March, 26 2015 - San Jose - CA - USA > > > Attendees: > > > Angelos Manousaridis <[email protected]> > Bob Moragues <[email protected]> > Chris Kohn > Guennadi Liakhovetski <[email protected]> > Hans Verkuil <[email protected]> > Hyun Kwon > Karthik Poduval <[email protected]> > Laurent Pinchart <[email protected]> > Mauro Carvalho Chehab <[email protected]> > Michal Lebik > Mohammed CHERIFI [email protected] > Rafael Chehab <[email protected]> > Ron Birkett > Schuyler Patton > Shuah Khan <[email protected]> > > 1) Media Controller support for DVB > Mauro presented a set of slides (add link) showing how the DVB pipelines look > like and underlined that several topics needs to be addressed by the Media > controller: > > a) dynamic creation/removal of pipelines > b) change media_entity_pipeline_start to also define the final entity > c) how to setup pipelines that also envolve audio and DRM? > d) how to lock the media controller pipeline between enabling a pipeline and > starting it, in > > How to do complex pipelines in DVB? > > - The DVB demux can filter MPEG-TS traffic (either in hardware or in > software) and can send multiplexed TS to the dvr node, elementary streams to > the demux node and can create network interfaces for elementary streams (ES) > via the net node. > - a given set of elementary streams can go to one of those three options > only, or it can be sent directly to a GPU and/or an ALSA pipeline. > - there is support for hardware PID filtering at the Kernel, but no support > (yet) for a real hw demuxer that splits the MPEG TS into separate DMA MPEG-TS > and/or ES streams. > - frontend device node is to be attached to the demod entity and it will > control the demod, the tuner and a possible LNA via the active Media > Controller links. > - dvr/net/demux device nodes are attached to the demux entity. > - the net interfaces are not (yet) represented via MC: we need the ability to > remove entities dynamically for that, and we are not really sure if we want > this at all. So, it as agreed to wait for support for removing entities to > arrive, then this need can be discussed again. > - For now we can safely assume that there is only one Satellite Equipment > Control (SEC) in each active data path that goes through a tuner/demod. So > each frontend will control just one SEC. > Should we encounter really complex scenarios, then we should consider > having device nodes for SEC entities. > > It was decided that: > - The Satellite Equipment Control (SEC) should be an entity, linking them to > the connector > - Deprecated osd, teletext, video and audio device nodes are only used in > av7110. The av7110 driver uses lots of deprecated stuff, we should move this > to staging and deprecate the whole driver and see who starts yelling. > - Document the high-level overview of DVB (Mauro). Layout needs to be changed > to be in line with the other APIs (Hans?). > - Mauro will rename “frontend” entity to “demod” at the Media Controller, as > the frontend is actually a set of elements. > - Laurent will prepare a proposal of reporting device nodes via a new entity > properties API addition > > 2) Media Tokens > > Shuah submitted some RFC Patches: > https://git.kernel.org/cgit/linux/kernel/git/shuah/linux.git > > - Changes from the previous RFC: > - simplified after switching au0828 to vb2 > - token created by the bridge driver > > It was decided that: > - Preference for using the Media Controller. That requires that MC support > for Alsa is added, the usbaudio driver then needs to find and hook into the > MC from the bridge driver. > - The RFC patches will help to identify on what places the driver should be > touched > - Shuag Shuag -> Shuah :-) > from Samsung is willing to do the changes at ALSA; Rafael is willing to add > MC support at au0828/au8522. > - Media controler dev (mdev) will have to be created as a dev resource on the > parent device to the bridge device similar to media tokens > - Need a new media_device_create() interace to allocate it as a device > resource. This routine will either return media device if one is created or > create it. > - Both au0828 and ALSA will first call media_device_create(). Coordinate > register/unregister?? > > 3) FPGA/Project ARA: dynamic reconfiguration (http://www.projectara.com/) > - partial pipeline removal: controlled removal in the case of FPGA > reconfiguration. subdevs/entities will be removed: unsupported today. > - no notification in MC when things change: we likely need an event mechanism. > - adding entities: doable, might need to add links in a 'pending' state, to > be made into a normal link once all streaming is stopped. > - subdevs: add refcounting, remove calls subdev_unregister(). Internal > release callback when the refcount goes to 0. > - Removal of subdevs will lead to holes (missing entities) in the MC graph. > - reuse entity IDs? Mauro doesn't like it, Laurent/Hans undecided. > - if one entity has a pointer to another it has to take a refcount. Possible > locking issues. Needs analysis. > > 4) Update on ongoing projects > > 5) Android Camera v3 > > The Khronos OpenKCam API addresses the same needs as the Android Camera HAL > v3 API, and is quite similar in concept. We should make sure that our API can > support OpenKCam. > The specification isn't public, but it's based on the FCam API (Nokia > research project) which should be available publicly. Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
