[linux-dvb] SAA7146 DMA buffer overflow - delayed interrupts ?

Ingo Schneider mail at ingo-schneider.de
Sat Feb 25 14:52:39 CET 2006

Hi again !

I now did a very different test:
While running the backup with dump, I used the "echo" port to measure 
how long it takes for a character to be echoed back to my second machine,
and then immediately writing the next character.

And while the log indicated that there was no SAA7146 interrupt for 
70ms, the longest time measured for getting the character back was 16 ms 
(tested for 3 minutes with 400000 roundtrips).

It seems that the SAA7146 Interrupts are delayed for a very long time 
while the rest of the system runs fine - very strange !

Ingo Schneider.

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