On 03/21/17 11:42, Niklas Söderlund wrote: > On 2017-03-20 16:57:54 +0100, Hans Verkuil wrote: >> On 03/20/2017 03:11 PM, Russell King - ARM Linux wrote: >>> On Mon, Mar 20, 2017 at 02:57:03PM +0100, Hans Verkuil wrote: >>>> On 03/20/2017 02:29 PM, Russell King - ARM Linux wrote: >>>>> It's what I have - remember, not everyone is happy to constantly replace >>>>> their distro packages with random new stuff. >>>> >>>> This is a compliance test, which is continuously developed in tandem with >>>> new kernel versions. If you are working with an upstream kernel, then you >>>> should also use the corresponding v4l2-compliance test. What's the point >>>> of using an old one? >>>> >>>> I will not support driver developers that use an old version of the >>>> compliance test, that's a waste of my time. >>> >>> The reason that people may _not_ wish to constantly update v4l-utils >>> is that it changes the libraries installed on their systems. >>> >>> So, the solution to that is not to complain about developers not using >>> the latest version, but instead to de-couple it from the rest of the >>> package, and provide it as a separate, stand-alone package that doesn't >>> come with all the extra baggage. >>> >>> Now, there's two possible answers to that: >>> >>> 1. it depends on the libv4l2 version. If that's so, then you are >>> insisting that people constantly move to the latest libv4l2 because >>> of API changes, and those API changes may upset applications they're >>> using. So this isn't really on. >>> >>> 2. it doesn't depend on libv4l2 version, in which case there's no reason >>> for it to be packaged with v4l-utils. >> >> Run configure with --disable-v4l2-compliance-libv4l. >> >> This avoids linking with libv4l and allows you to build it stand-alone. >> >> Perhaps I should invert this option since in most cases you don't want to >> run v4l2-compliance with libv4l (it's off by default unless you pass the >> -w option to v4l2-compliance). >> >>> >>> The reality is that v4l2-compliance links with libv4l2, so I'm not sure >>> which it is. What I am sure of is that I don't want to upgrade libv4l2 >>> on an ad-hoc basis, potentially causing issues with applications. >>> >>>>>> To test actual streaming you need to provide the -s option. >>>>>> >>>>>> Note: v4l2-compliance has been developed for 'regular' video devices, >>>>>> not MC devices. It may or may not work with the -s option. >>>>> >>>>> Right, and it exists to verify that the establised v4l2 API is correctly >>>>> implemented. If the v4l2 API is being offered to user applications, >>>>> then it must be conformant, otherwise it's not offering the v4l2 API. >>>>> (That's very much a definition statement in itself.) >>>>> >>>>> So, are we really going to say MC devices do not offer the v4l2 API to >>>>> userspace, but something that might work? We've already seen today >>>>> one user say that they're not going to use mainline because of the >>>>> crud surrounding MC. >>>>> >>>> >>>> Actually, my understanding was that he was stuck on the old kernel code. >>> >>> Err, sorry, I really don't follow. Who is "he"? >> >> "one user say that they're not going to use mainline because of the >> crud surrounding MC." >> >>> >>> _I_ was the one who reported the EXPBUF problem. Your comment makes no >>> sense. >>> >>>> In the case of v4l2-compliance, I never had the time to make it work with >>>> MC devices. Same for that matter of certain memory to memory devices. >>>> >>>> Just like MC devices these too behave differently. They are partially >>>> supported in v4l2-compliance, but not fully. >>> >>> It seems you saying that the API provided by /dev/video* for a MC device >>> breaks the v4l2-compliance tests? >> >> There may be tests in the compliance suite that do not apply for MC devices >> and for which I never check. The compliance suite was never written with MC >> devices in mind, and it certainly hasn't been tested much with such devices. >> >> It's only very recent that I even got hardware that has MC support... >> >> From what I can tell from the feedback I got it seems to be OKish, but I >> just can't guarantee that the compliance utility is correct for such devices. >> >> In particular I doubt the streaming tests (-s, -f, etc.) will work. The -s >> test *might* work if the pipeline is configured correctly before running >> v4l2-compliance. I can't imagine that the -f option would work at all since >> I would expect pipeline validation errors. > > I successfully use v4l2-compliance with the -s option to test the > Renesas R-Car Gen3 driver which uses MC, I first have to setup the > pipeline using media-ctl. I have had much use of the tool and it have > helped me catch many errors in the rcar-vin driver both on Gen2 (no MC > involved) and Gen3. And yes the -f option is only usable on Gen2 where > MC is not used. Ah, good to hear that -s works with MC. I was not sure about that. Thanks for the feedback! Regards, Hans
