Hello, Steve. I tried the fix you suggested the other day, but I still end up with the same error as before.

I thought it'd help if I show what exactly I'm seeing in my console output when I try to run both dump978 & dump1090 at the same time.

Robert L. Hudspeth

On Thu, Aug 15, 2019 at 1:15 PM Steve Markgraf <steve@steve-m.de> wrote:

Hi Robert,

On 15.08.19 17:50, Hudspeth, Robert Lee wrote:
> I'm trying to run utilities that capture 978
> <https://github.com/mutability/dump978> & 1090Mhz
> <https://github.com/mutability/dump1090> traffic simultaneously, but I
> can't seem to stop rtl_sdr from allocating too many zero-copy buffers
> and preventing both programs from running simultaneously (I'd like to
> cut down from 15). I've been through librtlsdr.c and rtl_adsb.c with the
> hope of manually changing some variable that will let me accomplish this
> to no avail. 

Just increase the usbfs memory limit, the default is only 16MB.
Either write the new size, or completely disable the limit with:

echo 0 > /sys/module/usbcore/parameters/usbfs_memory_mb

Regards,
Steve