Hello, Actually, relaunching the call of libusb_control_transfer in rtlsdr_demod_write_reg does the trick for all three messages and sets the frequency correctly without error message. This seems to fix also the gain not being set. The call of rtlsdr_demod_read_reg is necessary before recalling libusb_control_transfer, if we juste call libusb_control_transfer a 2nd time this doesn't work. The patch in my initial post is not necessary if this one is applied. Pull request: https://github.com/steve-m/librtlsdr/pull/58 Regards Le mercredi 2 octobre 2019, 08:25:54 CEST Fab Stz a écrit : > Hello, > > When doing a setFrequency I usually have this error afterwards and the > frequency is actually not changed > > rtlsdr_demod_write_reg failed with -9 > r82xx_write: i2c wr failed=-9 reg=17 len=1 > r82xx_set_freq: failed=-9 > > By searching around I found this commit that makes the trick for me. > https://github.com/keenerd/rtl-sdr/commit/ > 9ed9ffa37e24f3293fa960cfcd74909ac3e9996c > > This will actually really set the frequency and remove the last 2 errors > related to "r82xx". The only error remaining is then > > rtlsdr_demod_write_reg failed with -9 > > > If you can include that upstream that would be nice. > I created a pull request here : > https://github.com/steve-m/librtlsdr/pull/56 > > Actually the commit is part of a large PR that you may be interested in ? > https://github.com/keenerd/rtl-sdr/pull/8 > > Regards,

This is weird, I haven't seen this issue before. Which USB host controller are you using, which OS and which version of libusb?

How often does this problem occur?

Any advice ?

Have you tried using a more recent Kernel?

there is either some issue with your hardware or driver support of your system