kuiper
Posts: 1
Joined: Sat May 23, 2020 8:42 pm

rtlsdr not working read/write errors

Sat May 23, 2020 9:10 pm

I have a RPi Model B rev 2 which previously worked with RTL SDR and the RTL2832U DVB-T in 2015. My daughter upgraded to stretch about two years ago and I found recently that it no longer worked, giving register read and write errors. There was a discussion if this (or at least a similar) problem on the Github RPi forum in July of 2019 which indicated a USB error that was fixed and committed. I upgraded to buster to get this fix, but the problem persists:

Code: Select all

[email protected]:~ $ cat rtlsdr.txt 
[email protected]:/opt/rtl-sdr/build $ sudo rtl_test 
Found 1 device(s):
  0:  Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM
Found Rafael Micro R820T tuner
r82xx_write: i2c wr failed=-1 reg=1a len=1
r82xx_init: failed=-1
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
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 
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
r82xx_write: i2c wr failed=-1 reg=0a len=1
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
(five more pairs)
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
WARNING: Failed to set sample rate.
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
rtlsdr_write_reg failed with -1
rtlsdr_write_reg failed with -1

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...
Allocating 15 zero-copy buffers
Failed to submit transfer 0
Please increase your allowed usbfs buffer size with the following command:
echo 0 > /sys/module/usbcore/parameters/usbfs_memory_mb

Library error -5, exiting...
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_write_reg failed with -4
Increasing the buffer size with the command shown had no effect, even on the buffer size error. This is probably a consequence of the register read/write errors.

The DVB-T dongle works fine under Ubuntu-18 on my Dell laptop.

Any suggestions would be greatly appreciated.

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