Hello, we discovered several problems with the ngene based dual DVB cards. The problems occur with the Digital Devices Cine S2 Dual DVB-S2 device (Linux4Media cineS2 DVB-S2 Twin Tuner), the clones like Mystique SaTiX S2 Dual should also be affected. We are using the ngene drivers from the linuxtv repository http://linuxtv.org/hg/v4l-dvb and the firmware version 15 provided by Digital Devices. *Setup* ******************************************* OpenSuse Linux 11.0 Linux anna 2.6.25.20-0.5-pae #1 SMP 2009-08-14 01:48:11 +0200 i686 i686 i386 GNU/Linux DVB drivers: http://linuxtv.org/hg/v4l-dvb (ngene) 2e0444bf93a4 (changeset 14233:2e0444bf93a4, date: Mon Feb 22 10:58:43 2010 -0300) module loaded with modprobe ngene one_adapter=0 *Usage* ******************************************* We slightly modified the latest version of szap-s2 (available from http://mercurial.intuxication.org/hg/szap-s2/ ); see attached .tar.gz tar xvfz modified_szap_s2.tar.gz make Most importantly, the modified version prints out the total delay in seconds of main() to allow for easier debugging. *Problem A* ******************************************* Two running instance of szap-s2 are used: a) one for changing channels between "Das Erste" (Astra 19.2E) and "ZDF" (Astra 19.2E) b) the other one for recording from "Das Erste" (or any other channel) Result: When only a) is running, channel tuning times between the two different transponders of "Das Erste" and "ZDF" are around 0.5 secs. This is really good. However, when b) is started in parallel, these times increase to 1.5 to 1.8 seconds. This is not good. How to reproduce? 1) in one shell, run ./run_szap-s2_adapter0.sh | grep Delay You will see Delay : 0.560508 Delay : 0.545771 Delay : 0.609781 Delay : 0.593796 Delay : 0.649772 Delay : 0.614023 .. 2) in parallel in another shell, run ./szap-s2 -S 1 -H -c channels_DVB-S2_transponder_switch.conf -a 1 -n 1 -r Immediately, you will see in 1) Delay : 1.525178 Delay : 1.781971 .. *Problem B* ******************************************* After reproducing Problem A, we terminate process 2) by hitting Ctrl-C. Even then, channel tuning time stay high in process 1), you will still see Delay : 1.773303 Delay : 1.781734 Delay : 1.749948 .. This is not good. *Problem C* ******************************************* What is even worse: Very often, you will soon run into trouble: After a very iterations, you will see: Delay : 21.616521 Delay : 21.773475 Delay : 21.765678 This means that tuning was not possible anymore at all. In this situation, it always helps to re-load the module by runing: su -c "rmmod ngene && modprobe ngene one_adapter=0" *Problem D* ******************************************* When terminating process 1) and immediately restarting it, channel tuning times - again - stay high. This is not good. Often you will also see Problem C then. *Problem E* ******************************************* Go back to reproducing Problem A (process 1 and 2 are running), and the continuously start and terminate process 2) by hitting Ctrl-C again and again. Sooner or later, you will see Problem C occur then. *Remark* ******************************************* It _seems_ that, after terminating all szap-s2 processes, and waiting 1 to 2 minutes, and then restarting szap-s2 again, the failures/problems seem to be gone _without_ reloading the module. thanks for your help, Andreas Besse
Attachment:
modified_szap_s2.tar.gz
Description: GNU Zip compressed data
