Em Sun, 12 Mar 2017 22:29:04 +0100 Pavel Machek <pavel@xxxxxx> escreveu: > Mid-layer is difficult... there are _hundreds_ of possible > pipeline setups. If it should live in kernel or in userspace is a > question... but I don't think having it in kernel helps in any way. Mid-layer is difficult, because we either need to feed some library with knowledge for all kernel drivers or we need to improve the MC API to provide more details. For example, several drivers used to expose entities via the generic MEDIA_ENT_T_DEVNODE to represent entities of different types. See, for example, entities 1, 5 and 7 (and others) at: https://mchehab.fedorapeople.org/mc-next-gen/igepv2_omap3isp.png A device-specific code could either be hardcoding the entity number or checking for the entity strings to add some logic to setup controls on those "unknown" entities, a generic app won't be able to do anything with them, as it doesn't know what function(s) such entity provide. Also, on some devices, like the analog TV decoder at: https://mchehab.fedorapeople.org/mc-next-gen/au0828_test/mc_nextgen_test-output.png May have pads with different signals on their output. In such case, pads 1 and 2 provide video, while pad 3 provides audio using a different type of output. The application needs to know such kind of things in order to be able to properly setup the pipeline [1]. [1] this specific device has a fixed pipeline, but I'm aware of SoC with flexible pipelines that have this kind of issue (nobody upstreamed the V4L part of those devices yet). Thanks, Mauro
