InvalidInput for Camera::start with a valid config, only in release mode

[joelgallant]

When running a --release build (no non-standard options), Camera::start, which functions correctly with debug mode, throws the error: Io(Os { code: 22, kind: InvalidInput, message: "Invalid argument" }). I cannot adjust the options correctly to get it to not do this, and the options I select do show up when doing camera.resolution, etc.

As far as I can tell, it derives from here:
https://github.com/loyd/rscam/blob/5e7a429fe1faed82925832c5ea5d3c9dadb6b239/src/v4l2.rs#L87-90

This led me down the path of enabling the no_wrapper feature, which did work in release mode, but changed the available formats, frame rates, etc. that it would allow me to use. I assume that differences between release and debug are not intentional, so I'd rather avoid that road.

It's worth mentioning that I am cross compiling for armv7-unknown-linux-gnueabihf.

I'm going to look in to this issue since it does matter to me for my project, but if you have any ideas I'd love any tips you might have?

[joelgallant]

On second look, I'm wrong about where the error is coming from - I believe it's alloc_buffers and mmap.

Specifically, v4l2_mmap returns usize::MAX and triggers the check_io!. The error is last_os_error, which is incorrect in this case as far as I can tell - it reports as InvalidArgument (which probably does make sense, since this is linking to v4l2_mmap, that doesn't report it's error using last_os_error).

[loyd]

this is linking to v4l2_mmap, that doesn't report it's error using last_os_error

v4l2_mmap uses errno, according to the documentation

It's worth mentioning that I am cross compiling for armv7-unknown-linux-gnueabihf.

I'll try to reproduce your problem as soon as I get my raspberry back.

[joelgallant]

I noticed that it does say it sets errno, when printing last_os_error before/after v4l2_mmap, it doesn't change - which doesn't mean it's not working.

[skligys]

I am seeing a similar error in Camera::start (also cross-compiling to Pi), also only in --release build:

I/O error: Value too large for defined data type (os error 75)

Strangely enough, if I clone rscam's source locally and build it:

[dependencies]
rscam = { path = "vendor/rscam" }

everything works just fine. Was the failure fixed since 0.5.4 release?

[jbolila]

Compiling locally on a raspberry pi, also gives an error when compiled with --release.

Comparing both strace output the issue happens on the following call:

ioctl(3, VIDIOC_REQBUFS, {count=2, type=V4L2_BUF_TYPE_VIDEO_CAPTURE, memory=V4L2_MEMORY_MMAP}) = 0 ({count=2})
ioctl(3, VIDIOC_QUERYBUF, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, index=0, memory=V4L2_MEMORY_MMAP, m.offset=0, length=307200, bytesused=0, flags=0x2000 /* V4L2_BUF_FLAG_??? */, ...}) = 0
write(2, "thread '", 8thread ')                 = 8
write(2, "main", 4main)                     = 4
write(2, "' panicked at '", 15' panicked at ')         = 15
write(2, "called `Result::unwrap()` on an "..., 113called `Result::unwrap()` on an `Err` value: Io(Os { code: 22, kind: InvalidInput, message: "Invalid argument" })) = 113
write(2, "', ", 3', )                      = 3

compared with the debug version:

ioctl(3, VIDIOC_REQBUFS, {count=2, type=V4L2_BUF_TYPE_VIDEO_CAPTURE, memory=V4L2_MEMORY_MMAP}) = 0 ({count=2})
ioctl(3, VIDIOC_QUERYBUF, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, index=0, memory=V4L2_MEMORY_MMAP, m.offset=0, length=307200, bytesused=0, flags=0x2000 /* V4L2_BUF_FLAG_??? */, ...}) = 0
mmap2(NULL, 307200, PROT_READ|PROT_WRITE, MAP_SHARED, 3, 0) = 0x76c02000
ioctl(3, VIDIOC_QUERYBUF, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, index=1, memory=V4L2_MEMORY_MMAP, m.offset=0x4b000, length=307200, bytesused=0, flags=0x2000 /* V4L2_BUF_FLAG_??? */, ...}) = 0
mmap2(NULL, 307200, PROT_READ|PROT_WRITE, MAP_SHARED, 3, 0) = 0x767b5000
ioctl(3, VIDIOC_QBUF, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, index=0, memory=V4L2_MEMORY_MMAP, m.offset=0, length=307200, bytesused=0, flags=V4L2_BUF_FLAG_MAPPED|V4L2_BUF_FLAG_QUEUED|0x2000, ...}) = 0
ioctl(3, VIDIOC_QBUF, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, index=1, memory=V4L2_MEMORY_MMAP, m.offset=0x4b000, length=307200, bytesused=0, flags=V4L2_BUF_FLAG_QUEUED|0x2000, ...}) = 0
ioctl(3, VIDIOC_STREAMON, [V4L2_BUF_TYPE_VIDEO_CAPTURE]) = 0

I'm using the latest version (v0.5.4)

[chris-ricketts]

I've just encountered this cross-compiling to armv7-unknown-linux-gnueabihf as well.
However, in this case the error occurs when built in debug, with --release it works.

This is version 0.5.5