Re: IDE + SMP Lockup (no OOPS) in 2.2.12, 2.2.10

Alan Cox (alan@lxorguk.ukuu.org.uk)
Fri, 1 Oct 1999 20:19:34 +0100 (BST)


> > Well serial is a medium that is almost guaranteed to lose data once in
> > a while ;-)
>
> Ok. Tell me: Why is the PCI serial chip with 128 byte buffer
> experiencing overruns, while the chip soldered to my motherboard
> (probably in one of those SMC multi-io chips (*)) with only 16 byte
> buffer is NOT dropping characters?

Because the IDE layer disables the shared IRQ in question for periods of
time of you dont have hdparm -u set, and for some periods of time anyway.

Basically its the IDE code being obnoxious. Fixing the IDE locking would
improve this, but would be a real pain because older IDE controllers you
want to disable_irq and stuff to avoid nasty performance problems.

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