Subject: Re: port-i386/4830: NE2000 ethernet board interrupt trouble
To: None <current-users@NetBSD.ORG>
From: Jason Thorpe <thorpej@nas.nasa.gov>
List: netbsd-bugs
Date: 01/16/1998 14:40:42
On 16 Jan 1998 22:14:19 GMT
tron@lyssa.owl.de (Matthias Scheler) wrote:
> So that bug can occur on a system running with correct hardware
> settings, too?
It can happen on any fast machine... as far as I can tell, it's purely
a function of how fast your processor can do this:
int i = 5000;
while (i--)
;
> I agree that this kind of bugs exist. But reading his bug report I had
> the impression that his fix was kludge to give his poor overstressed
> hardware time to recover. The 337 MHz indicates that he's not only
> overclocking the CPU but the system bus so that any kind of failures
> of the I/O hardware are a logical consequence. I really would like to
> know if the bug can be reproduced on a system without overclocked bus
> speed.
>
> > A delay in that loop is appropriate.
>
> Can't it cause reduced throughput on slow systems?
Umm... From the line numbers listed in his patch, it certainly looked
like the additional delay was needed in dp8390.c:dp8390_stop(). Did
I misread something?
Given that he said the card worked if he did:
ifconfig ne0 down
ifconfig ne0 up
...it leads me to believe that the dp8390_stop() in dp8390_config() didn't
actually put the chip in the expected state, which is why the reset caused
by the down/up cycle worked; the chip had entered that state later, and took
less time to recover the next time around.
Am I missing something here?
Jason R. Thorpe thorpej@nas.nasa.gov
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