[linux-dvb] Aver761 FBUS/FDSR - dvb-bt8xx questions

[Hamish Moffatt <hamish@cloud.net.au>]

I'm trying to debug my FDSR/FBUS problems on the Aver761.
It's possible that these are just caused by excessive PCI bus
latency, but I haven't had any success at all in fixing this
by tweaking the latency timer.

I've got a couple of questions about the bt878 and dvb-bt8xx drivers.
Can somebody here explain a couple of things for me?

Firstly, what is the function of the RISC program? Where is the program
itself in the code? (Is the bt878_risc_program() function all there is
to it?)

Secondly, I notice that in dvb-bt8xx, a bunch of interrupts are ignored
on the Twinhan DST card:
BT878_APABORT | BT878_ARIPERR | BT878_APPERR | BT878_AFBUS

Why is this? Any possibility that FBUS should be ignored on the 761?
I also have FDSR interrupts though and that seems to be more serious.

It looks like the FDSR interrupt is generated when the RISC program is
going awry. Under what conditions would that occur? (FIFO overflow?)

Finally, when bt878.c's interrupt handler clears the interrupt 20 times
without it going away, it declares a lockup and disables all interrupts,
including the one that handles data transfer (ARISCI). Is it better just
to disable the interrupt that locked up? Alternatively, reset by
switching off the RISC engine, fifo etc then restart?


It feels as if this problem has just started within the last 1-2 months.
My setup (MythTV 0.16 on linux 2.6.8.1) was stable for months before
that. Disk setup hasn't changed, nor graphics nor sound, so I/O load
shouldn't be higher. Myth's CPU usage may have gone up slightly.

I did switch to using the local APIC (since it's stable on nForce2 as of
linux 2.6.6 or so) but I think I had this problem before then.

I couldn't spot anything in CVS that would make it worse. Some of the
recent changes might help though.


thanks,
Hamish
-- 
Hamish Moffatt VK3SB <hamish@debian.org> <hamish@cloud.net.au>