This message looks coming from libusb. Maybe you check that lib source to understand what error code 5 stands for.... Have you tried to run app as root ? Le 6 oct. 2013 22:34, "Dan" &lt;yo3ggx(a)gmail.com <mailto:yo3ggx@gmail.com>> a écrit : Hi all, I have compiled and installed rtl-sdr on CentOS 6 following instructions. Everything compiles without errors, but: - when I run rtl_test I get the following errors: Found 1 device(s): 0: ezcap USB 2.0 DVB-T/DAB/FM dongle Using device 0: ezcap USB 2.0 DVB-T/DAB/FM dongle Found Rafael Micro R820T tuner Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6 Info: This tool will continuously read from the device, and report if samples get lost. If you observe no further output, everything is fine. Reading samples in async mode... cb transfer status: 5, canceling... cb transfer status: 5, canceling... cb transfer status: 5, canceling... cb transfer status: 5, canceling... cb transfer status: 5, canceling... cb transfer status: 5, canceling... cb transfer status: 5, canceling... cb transfer status: 5, canceling... Library error 0, exiting... If I run rtl_tcp I get the following errors when the client tries to connect: Found 1 device(s). Found Rafael Micro R820T tuner Using ezcap USB 2.0 DVB-T/DAB/FM dongle Tuned to 100000000 Hz. listening... Use the device argument 'rtl_tcp=192.168.33.99:8767 <http://192.168.33.99:8767>' in OsmoSDR (gr-osmosdr) source to receive samples in GRC and control rtl_tcp parameters (frequency, gain, ...). client accepted! set freq 145000000 cb transfer status: 5, canceling... cb transfer status: 5, canceling... rtlsdr_demod_write_reg failed with -4 rtlsdr_demod_read_reg failed with -4 rtlsdr_demod_write_reg failed with -4 rtlsdr_demod_read_reg failed with -4 set sample rate 1024000 rtlsdr_demod_write_reg failed with -4 rtlsdr_demod_read_reg failed with -4 rtlsdr_demod_write_reg failed with -4 rtlsdr_demod_read_reg failed with -4 rtlsdr_demod_write_reg failed with -4 rtlsdr_demod_read_reg failed with -4 rtlsdr_demod_write_reg failed with -4 rtlsdr_demod_read_reg failed with -4 rtlsdr_demod_write_reg failed with -4 rtlsdr_demod_read_reg failed with -4 rtlsdr_demod_write_reg failed with -4 rtlsdr_demod_read_reg failed with -4 rtlsdr_demod_write_reg failed with -4 rtlsdr_demod_read_reg failed with -4 rtlsdr_demod_write_reg failed with -4 rtlsdr_demod_read_reg failed with -4 set freq correction 4 rtlsdr_demod_write_reg failed with -4 rtlsdr_demod_read_reg failed with -4 rtlsdr_demod_write_reg failed with -4 rtlsdr_demod_read_reg failed with -4 worker cond timeout Signal caught, exiting! comm recv bye Signal caught, exiting! all threads dead.. listening... The same client connects without errors to another rtl_tcp instance on a Windows 7 computer, with the same module. Any help is greatly appreciated. Thanks, Dan

As far as I can tell, CentOS 6.4 uses libusb 0.1.12, released in August 2010. This is over three years old! A *lot* of bug fixes and improvements happen in three years.

Age has nothing to do with it.

My suggestion would be to grab an old libusb1 RPM and rebuild it. It should be trivial and the result is installable alongside the old libusub.

You're using CentOS. This is an enterprise Linux system, designed for running servers. This means the software is chosen because it is known to be stable, so it is usually missing the latest features. As far as I can tell, CentOS 6.4 uses libusb 0.1.12, released in August 2010. This is over three years old! A *lot* of bug fixes and improvements happen in three years.

The problem you are experiencing has likely been fixed at some point within this time, so your solutions are to install a newer libusb version, or better yet, switch to a Linux distro that is more suited to this kind of work. CentOS is great if you want to run a database server, but not so good if you want to experiment with the very latest gadgets!

Cheers, Adam.

forget rpm, just install libusb by downloading the tarball at http://www.libusb.org/ configure make make install just my two cents

So you're saying no useful work was done on libusb in three years?

Granted I haven't looked at the commit history but it seems a bit unlikely.

I have tried to compile both the one from www.libusb.org and the one from git. After recompiling rtl-sdr with the new libraries the errors are the same....

Any other hints?

Only to use the latest kernel code.

If you see the problem with the latest kernel (from Linus' git - the latest packaged by CentOS is irrelevant) and using code from git.libusb.org/libusb.git by way of e.g. LD_LIBRARY_PATH then I would be interested in seeing a libusb debug log. See http://libusb.org/wiki/debug for a copypaste-able instruction on how to generate one. Thanks!

//Peter

I cannot change the kernel on the system I intend to use the dongle, as it provides other services which cannot be interrupted..

Before this I've fully uninstalled the previous version and set the environment variables: LIBUSB_LIBS and LIBUSB_CFLAGS before running ./configure for rtl-sdr

That's a bit indirect. The best way is to run ldd ./myapp

I continue to maintain that all this advice about installing "latest" without knowing what's up is not likely to work.

The stock libusb1 rpm from Koji works just fine, I would not even bother rebuilding it, just pull off an F14 repo.

Find what the problem is by running strace ./rtl-sdr and matching ioctls to the code.

I continue to maintain that all this advice about installing "latest" without knowing what's up is not likely to work. The stock libusb1 rpm from Koji works just fine, I would not even bother rebuilding it, just pull off an F14 repo.

Dan wrote: I can understand that you can not upgrade kernel on the final system, but it would be very helpful if you could test on a separate system, with similar hardware, with a new kernel, to see if the problem persists. That sounds good. It is important that you have uninstalled the version provided by the CentOS package. Pete Zaitcev wrote: ldd is a good way to see what libraries will actually be loaded by a given program. If indeed the CentOS package has been uninstalled then ldd should confirm that the correct library file is being loaded. It's not about what will likely make things work, it's about doing debugging with the current state of the code, so that I know that I haven't already fixed the problem in libusb.git and so that I know exactly what code is being used when the error occurs. Since there are commits in libusb.git which are not included in those binaries it is significantly more helpful to use the git code for testing. Please don't do that, it is not helpful. Please focus on creating a debug log as described on http://libusb.org/wiki/debug since that's very useful for those of us who know the libusb code. Thanks //Peter

Dan wrote: Thanks! I'll take a look at this and get back to you.

//Peter