Em Fri, 29 Jun 2018 12:26:20 +0200 Hans Verkuil <hverkuil@xxxxxxxxx> escreveu: > On 06/29/18 12:06, Mauro Carvalho Chehab wrote: > > Em Thu, 28 Jun 2018 14:47:05 +0200 > > Hans Verkuil <hverkuil@xxxxxxxxx> escreveu: > > > >> On 06/28/18 13:37, Mauro Carvalho Chehab wrote: > >>> Em Thu, 17 May 2018 16:30:16 +0200 > >>> Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx> escreveu: > >>> > >>>> There is no way to control the standard of subdevices which are part of > >>>> a media device. The ioctls which exists all target video devices > >>>> explicitly and the idea is that the video device should talk to the > >>>> subdevice. For subdevices part of a media graph this is not possible and > >>>> the standard must be controlled on the subdev device directly. > >>> > >>> Why isn't it possible? A media pipeline should have at least a video > >>> devnode where the standard ioctls will be issued. > >> > >> Not for an MC-centric device like the r-car or imx. It's why we have v4l-subdev > >> ioctls for the DV_TIMINGS API, but the corresponding SDTV standards API is > >> missing. > >> > >> And in a complex scenario there is nothing preventing you from having multiple > >> SDTV inputs, some of which need PAL-BG, some SECAM, some NTSC (less likely) > >> which are all composed together (think security cameras or something like that). > >> > >> You definitely cannot set the standard from a video device. If nothing else, > >> it would be completely inconsistent with how HDMI inputs work. > >> > >> The whole point of MC centric devices is that you *don't* control subdevs > >> from video nodes. > > > > Well, the way it is, this change is disruptive, as, as far as I remember, > > MC-based devices with tvp5150 already sets STD via the /dev/video device. > > Really? Which driver? I am not aware of this and I think you are mistaken. > Remember that we are talking about MC-centric drivers. em28xx is not MC-centric, > even though it has a media device. OMAP3. There are some boards out there with tvp5150. > > > > > If we're willing to add it, we'll need to be clear when one approach > > should be taken, and be clear that, if the SUBDEV version is used, the > > driver should not support the non-subdev option. > > Of course, but in the case of em28xx the tvp5150 v4l-subdev node is never > created, so this is not a problem. > > Regards, > > Hans > > > > >> > >> Regards, > >> > >> Hans > >> > >>> So, I don't see why you would need to explicitly set the standard inside > >>> a sub-device. > >>> > >>> The way I see, inside a given pipeline, all subdevs should be using the > >>> same video standard (maybe except for a m2m device with would have some > >>> coded that would be doing format conversion). > >>> > >>> Am I missing something? > >>> > >>> Thanks, > >>> Mauro > >>> > >> > > > > > > > > Thanks, > > Mauro > > > Thanks, Mauro
