On 02/04/2018 02:13 PM, Laurent Pinchart wrote: > Hi Hans, > > On Sunday, 4 February 2018 15:06:42 EET Hans Verkuil wrote: >> Hi Mauro, >> >> I'm working on adding proper compliance tests for the MC but I think >> something is missing in the G_TOPOLOGY ioctl w.r.t. pads. >> >> In several v4l-subdev ioctls you need to pass the pad. There the pad is an >> index for the corresponding entity. I.e. an entity has 3 pads, so the pad >> argument is [0-2]. >> >> The G_TOPOLOGY ioctl returns a pad ID, which is > 0x01000000. I can't use >> that in the v4l-subdev ioctls, so how do I translate that to a pad index in >> my application? >> >> It seems to be a missing feature in the API. I assume this information is >> available in the core, so then I would add a field to struct media_v2_pad >> with the pad index for the entity. >> >> Next time we add new public API features I want to see compliance tests >> before accepting it. It's much too easy to overlook something, either in >> the design or in a driver or in the documentation, so this is really, >> really needed IMHO. > > I agree with you, and would even like to go one step beyond by requiring an > implementation in a real use case, not just in a compliance or test tool. > > On the topic of the G_TOPOLOGY API, it's pretty clear it was merged too > hastily. We could try to fix it, but given all the issues we haven't solved > yet, I believe a new version of the API would be better. > It's actually not too bad as an API speaking as an end-user. It's simple and efficient. But this pad issue is a real problem. Regards, Hans
