Thanks for the explanation(s), David!
David Brownell wrote:
>> ehci_hcd 0000:00:13.2: MWI active
>
> That's the good one. It means that a more efficient PCI transaction
> will be used when writing memory ... "memory write invalidate" so the
> CPU data cache is managed with less overhead.
>
> In fact this is the first time I've ever seen that message. I think it's
> because your CPU has a relatively small CPU cacheline size. Larger
> ones prevent Linux from turning MWI (doesn't seem right to me, but
> that's the way it works for now).
Maybe there are not so many people trying to get USB 2.0 working on
old boxes? Mine is still working fine and I have a few spare parts
in case of failures :)
>> status a008 Async Recl FLR
> ^^^^^
>> command 010009 (park)=0 ithresh=1 period=256 RUN
>
> And that's the problem. The controller is scanning the async
> schedule ... but it shouldn't be, since it's not enabled in the
> command word. Where "scanning" means it's doing DMA to read
> an empty async schedule ring ... a LOT of DMA, keeping your
> network controllers from their DMA.
Hmm. DMA. Yes. I measured disk-I/O and found that it dropped from
about 24MB/s down to 2.3MB/s when ehci-hcd is loaded and active.
> This could well be the root cause of some problems other folk
> have reported. It's a "not supposed to be possible" thing.
So... this could still be an issue with the card or mainboard
or the combination of both?
> The only tricky thing about turning the async schedule on or
> off is that it's done in a non-blocking way. So my guess
> would be that on some code path ASE is cleared before ASS
> gets set, or there's a similar no-no ... likely a race of some
> kind, since not every system seems to experience such problems.
Could this eventually be caused/supported by some bad BIOS setting
concerning the PCI bus?
-dirk
--
D i r k F "o r s t e r l i n g
[EMAIL PROTECTED] http://r.zorbla.de/
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