Hello Forum,
i am using a vdr headless server with 3 Technisat Skystar USB tuners for satellite television streaming.
Before i used a raspberry pi 2 but because of limitations with its ethernet bandwith i went to odroid c2.
System is now armbian with self compiled vdr with vnsi plugin, both out of git repo.
System runs fine but after some hours (8h) a sporadic failure occurs and (USB?) system becomes unusable,
To get the 3 dvb-s2 tuners running i increased the urb pool (USB request block) with kernel parameter "coherent_pool=6M" in boot.ini.
I calculated that every of all 3 instances of driver needs about 512kB of USB buffer memory, without the option the first instance fails with error -12 (ENOMEM).
At first i put an option "coherent_pool=32M" to test but it seemed that this was ignored without any message.
I found a hint in another forum and tried 6M and that seemed to be taken and to be enough for my 3 tuner devices.
My first questions is: what are the limits for this parameter coherent_pool and what is the default value ?
Second: what can i do to increase stability of USB ?
Here the syslog after some hours:
WARN::urb_dequeue:780: urb->hcpriv == NULL; urb = ffffffc07a0c9000 status=-2
and then lots of
driver and application errors because of usb action errors:
dvb-usb2: i2c-error: out failed 68 = -110