Fix likely REQBUFS failure when memory still mapped #52
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
According to 7.52 ioctl - VIDIOC_REQBUFS:
Because many devices, e.g. v4l2loopback in particular, don't support
V4L2_BUF_CAP_SUPPORTS_ORPHANED_BUFS
it's better to ensure that the mmap buffers are closed before invokingVIDIOC_REQBUF
.This PR should correctly call
munmap()
first if using cpython. I haven't tested with other python implementations.Side note: v4l2loopback (in particular 0.13.x) has issues with denying REQBUFS even when it shouldn't - I'm just now working on a fix for that, too (see umlaeute/v4l2loopback#599).