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. 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 >
