Hi,
Gotta small problem, which I'm hoping that people involved with building
systems around the DC21285 can shed some light on.
I've got a card with a CY82C693UB (South bridge) in my EBSA285, with an
ESS1879 sound chip on the 82C693's ISA bus. The sound chip uses ISA DMA.
There is also a 3c592 net card on the PCI bus, Promise Ultra33 UDMA IDE
card, and an S3 Trio64V2 video card.
The problem I'm seeing is total deadlock of the SA110 when, eg, the
Ethernet is accessed while an ISA DMA is in progress to the sound chip.
I haven't tried DMAs to other devices yet.
When it deadlocks, the following always seems to be true:
1. SA110 address bus contains an address in the PCI I/O
space of the DC21285.
2. The SA110 MCLK is held high.
3. ABE is high (address bus enabled).
4. DBE toggles.
5. The ISA DMA is still running, playing the same snippet of audio
over and over again (since the SA110 can't update the SDRAM with the
next block). Hence, ISA -> PCI -> SA110 bus is still functional.
6. The PCI request and grant signals for the 82C693 are toggling.
7. The PCI request and grant signals for the DC21285 are also toggling.
8. Comparing these two grant signals, they appear to be anti-phase.
Note: other PCI masters appear to be ok.
The only way out of this state is a hardware reset. I've tried swapping
the slot that the Promise and the Southbridge use, but that doesn't affect
it - it still deadlocks when doing ISA DMA. I haven't yet checked to see
if this PCI I/O transaction that the SA110 is asking for is a read or a
write, but I should know that later tonight...
I suspect that this could be related to the Outbound write flush problem
(ie, issuing an outbound write flush to the DC21285 causes deadlock).
_____
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| | Russell King [EMAIL PROTECTED] --- ---
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