[PlanetCCRMA] Lockup on tar command over ssh

Adam Swift vikeul at omnitude.net
Sat Jun 21 07:20:13 PDT 2008

Michael Curtis <lists at moltenmercury.org> wrote:
> Sounds like it could be MMIO-related.  I've seen it in the kernel
> options, it's apparently (and I could be over-simplifying here) an
> option to deal with large amounts of data by batching up transfers.
> In any case, these options have been marked experimental for some time
> in the kernel but given Fedora's track record with such things, it
> wouldn't surprise me if it's turned on by default.  Of course, if it's
> not enabled, maybe turning it on may help.  If you're confident in
> rebuilding RPMs, you might try a custom CCRMA kernel with MMIO turned
> off (on?), or Fernando may be able to help here.

With a bit of a learning curve because I'm a slackware user normally,  
I compiled a custom kernel with CONFIG_8139TOO_PIO=y and everything  
else the same, which fixed it. That turns off MMIO/turns on PIO for  
the 8139too driver, so you were right. The default on Fedora kernels  
is =n because it improves performance as you said.

The real question is, why do I need that for the realtime kernel but  
not for the normal kernel?


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