HostAP Stability (fixed??)

Dave Hinkle hinkle at
Sun May 11 23:38:56 EDT 2003

Some more information for you guys if it will help.  We have about 100
soekris devices with hostap cards in them in the field.  We have been having
huge problems with locked up cards, but we thought it was due to power
supply problems on our solar equipment.

The cards lock up, and get very hot, like they're stuck in transmit mode or
something.  Most of them go down during heavy rainstorms, perhaps marginal
connectivity is a factor? Or perhaps it's a red hearing.

If you could post the patches for your workaround we would love to test them
to see if this is our problem, or if we do really have power system issues.

	Thanks much,


-----Original Message-----
From: Dave Hinkle [mailto:hinkle at] 
Sent: Sunday, May 11, 2003 9:57 PM
To: hostap at
Subject: RE: HostAP Stability (fixed??)

The vast majority of our routers are soekris based, and we're having
constant problems with locked up cards.  If you could make the work around
patches available, we would really appreciate it.


-----Original Message-----
From: Jouni Malinen [mailto:jkmaline at] 
Sent: Sunday, May 11, 2003 7:59 PM
To: hostap at
Subject: Re: HostAP Stability (fixed??)

On Sun, May 11, 2003 at 06:24:43PM +0100, Mike Saywell wrote:

> Bascially I was recompiling the kernel on one of my APs and noticed I
> had SMP enabled, so I disabled it (it's a single processor machine),
> and since doing this hostap hasn't locked up once!

> I'm a bit confused about the problems reported with soekris boards though,
> I wouldn't have thought people would be running an SMP kernel on them...

I think these are two separate issues, although they could be related. I
don't currently have easy access to an SMP host, so I have been waiting
with SMP testing. However, based on your findings, it would be enough to
just use SMP enabled kernel.. I'll do that at some point.

I have now borrowed a Soekris board (thanks Sam!) and can duplicate the
reported hang easily. This sure makes it easier to debug the issue. It
looks like kernel does not really hang, it just happens to be busy
looping in hardware interrupt handler.. I was able to use Prism2 tick
event to detect such hangs and write debugging code for reporting what
went wrong. In addition, I have code that is able to automatically
recover from such a hang.

I haven't committed these changes yet since they are just hiding the
real issue: RX events seem to be unmasked in some cases before they have
been processed. This will end up in a state where the card has RX event
and thus IRQ line asserted all the time. A tasklet is trying to process
the pending RX entries, but it does not get anything done since it is
constantly interrupted by the event that it is actually trying to clear.

Jouni Malinen                                            PGP id EFC895FA
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