Usb4java, JNA, IOCTL, library

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Hello,

I'll have a problem with a program which I code on my linux Pc, where a camera stream should be transmitted.

On Linux I use the Usb4java Library to access the Usb Device and prepair the camera for the streaming. Therefore I have to claim the 2 CameraInterfaces and have to send some byte codes....

On the other side I have to transmit an isochronuos transfer, which I'm going to practise over an Jna Library, because the Isochronuos transfer is not supported from the Usb4java
Lib. The JNA library uses the UsbFS Device Driver to transmit the data from the Device.

This procedure works like a charm on android, where ones the android usb.hardware.manager and also a library which uses the Jna were connected to the device and it's Interfaces.

On Linux I face the problem, that I can't access the device with 2 different libraries. When I claim an Interface from the usb camera with the Usb4java, the I'll get an error code from the JNA lib, that the device or resource is busy. If I release the interface from the Usb4java lib, then the JNA part works, but no more access over the Usb4java lib....

For a working stream both libs should be claimed to the Camera Interfaces.

The Jna lib is called UsbIso.

The author from the Usbiso lib hasn't tested his lib on linux up to now and also knows no solution for the problem. So perhaps someone here could help me out?

What I have tried:

Perhaps a Solution could be to use the high level API from Usb4java --> Javax.usb, or will I face then the same problem with the device busy error?
Any other suggestions would be welcome.

Thanks,

Peter

Posted 27-Aug-18 7:11am

Peter____

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Peter____ · Accepted Answer · 2019-03-03T21:35:00

Solution 1

So far I only use the rewritten JNA lib for performing the iso transfer now and Usb4Java lib for finding the devices and read out the descriptors.

Link for the project is:

GitHub - Peter-St/Linux_Jna_Kamera: Camera stream over Jna.[^]

Peter

Posted 3-Mar-19 21:35pm

Peter____

Updated 3-Mar-19 21:37pm

Comments

OriginalGriff 4-Mar-19 3:43am

Please don't repost if your answer does not appear immediately: all of these went to moderation and required a human being to review them for publication. In order to prevent you being kicked off as a spammer, both had to be accepted, and then I have to clean up the spares. Have a little patience, please!
I've deleted the spare ...

You also need to take care about what questions you answer - this one is over 6 months old, and it's unlikely that the OP is interested in a solution now. Posting solutions to old questions can look like rep point farming which will get you kicked off the site. I don't think that is what you intended with this post, so I won't start the process, but some of our more "trigger-happy" member may if you aren't careful. I'd suggest sticking to newer questions, particularly when your other solution is to your own question.

Richard Deeming 5-Mar-19 12:04pm

"... it's unlikely that the OP is interested in a solution now ..."

The solution was posted by the OP. :)

Peter____ 5-Mar-19 23:50pm

Yes, the only reason was, to answered the open question and not being showed any more in the open question part and link a project with a working solution, so everyone having such a problem, can have a look.

So far...
Peter