Hi Hans, Sergey, & the list. I'm running the latest v4l2-compliance (85ec2917 "v4l2-compliance: fix stateful encoder tests") against the Raspberry Pi vendor 5.4 kernel tree. That means the kernel isn't supporting V4L2_BUF_FLAG_NO_CACHE_[INVALIDATE|CLEAN] flags on the buffers, nor is anything advertising V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS. I'm getting failures in setupMmap. With patch "784be6a v4l2-utils: test cache_hints for MMAP queues" the test deliberately sets V4L2_BUF_FLAG_NO_CACHE_INVALIDATE and V4L2_BUF_FLAG_NO_CACHE_CLEAN on the buffers that it queues. Nothing in the kernel is expecting to manipulate those flags as the behaviour wasn't really defined before, but the test is failed if they aren't cleared. The v4l2 core would only clear them if the kernel includes the patch "f5f5fa7 media: videobuf2: handle V4L2 buffer cache flags", which currently means only linuxtv/master as that patch isn't even in 5.8-rc3. Is it really valid to look at the V4L2_BUF_FLAG_NO_CACHE_* flags at all if V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS isn't set? If the capability isn't advertised, surely the state of those bits is undefined. Thanks Dave
