[linux-dvb] Problems with KNC1 DVB-C

Rudy Zijlstra rudy at grumpydevil.homelinux.org
Mon Apr 30 11:42:56 CEST 2007

e9hack wrote:
> Oliver Endriss wrote:
>> Apparently it works in polling mode, but not in interrupt mode. Why?
>> Can someone else confirm problems with this card type
>> (Terratec Cinergy 1200 DVB-C, sub-system 0x153b:0x1156)?
>> Now I consider the following options:
>> - Add a module parameter to disable irq mode.
>> - Turn off irq mode for card type 0x153b:0x1156.
>> - Turn off irq mode for the TDA10021 frontend.
>> - Revert to polling mode for all cards.
>> :-(
>> Any opinions?
> The windows driver uses a reduced i2c bit rate. I've reduced the bit rate with the patch for the new DVB-C cards.
> Possible, it does solve the problem.
> - Hartmut
Original start configuration:

dual PIII with KNC-1, as well as 2 DVB-S cards, running
Was running with mild problems: the CAM on the KNC-1 was loosing sync.

P4 with Terratec Synergy, mostly being used for TS recordings. No 
apparent problems, running older kernel.

Then i got problems with the KNC-1, in that suddenly i could still tune 
but no longer got any data off the card.

Action 1: swap KNC-1 and Terratec.
Result 1: PIII system still giving same problems
P4 system with KNC-1 doing well.

thinking i was facing some weird application problem, i took an older 
Mythtv, build that on the P4 as a separate test system for DVB-C and 
slowly upgraded to most recent SVN head.
no problem found

upgrade the PIII to
The DVB-S cards work quit well (although diseqc seems to give 
intermitent problems), Terratec lost interupts, showing in i2c problems 
(see this thread).

Implement patch from Oliver Endriss.
On the dual PIII i2c works again, tuning works but i cannot get any data 
from the card......

upgrade the P4 to unpatched
The P4 with the KNC-1 works without problems.

At request i am willing to swap the Terratec and the KNC-1 to double 
verify the terratec also behaves well in the P4 with unpatched

Provisional conclusion:
The dual PIII is having interupt problems, most likely at least one PCI 
slot is no longer working correctly on interrupt level.
I am saying "at least one PCI" as i suspect the intermittent diseqc 
problems can also be caused by missing interupts.

Next action not yet known....

If anyone has a suggestion on how to test for problems on the other PCI 
slots, i'd be happy to know that.



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