Date: Sun, 22 Nov 2009 19:03:53 +0000
From: Chris Vine <chris@cvine.freeserve.co.uk>
To: Larry Finger <Larry.Finger@lwfinger.net>
Cc: wireless <linux-wireless@vger.kernel.org>,
	bcm43xx-dev@lists.berlios.de
Subject: Re: Fatal DMA error problem with netbook and BCM4312
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On Sat, 21 Nov 2009 00:15:12 +0000
Chris Vine <chris@cvine.freeserve.co.uk> wrote:
> WARM BOOT FROM KERNEL WITH WL MODULE INSTALLED
> 
> The patched kernel makes no change on a warm boot in the sense that
> if I warm boot after initialising the wireless device with the wl
> module then the b43 module appears to work correctly, both with and
> without the patch applied.
> 
> On the same stress test as mentioned above, I have not been able to
> induce the DMA errors nor kernel warnings.  It resolutely refuses to
> do anything except work correctly.

This is just to say that I have carried out further stress tests today
after warm booting to an unpatched linux-2.6.32-rc8 kernel with the b43
driver (on the assumption that unpatched is the least favourable case
for the driver).  This is a warm reboot from a 2.6.31.6 kernel which had
the wl driver installed.

I have created an extended period of high speed traffic on my wireless
lan and I cannot induce any errors at all with the b43 driver on a warm
reboot.

This makes me wonder whether the patch is just (partially) masking the
problem rather than actually dealing with it.

Chris

PS   The wl driver was compiled from
hybrid-portsrc-x86_32-v5.10.91.9.3.tar.gz available at
http://www.broadcom.com/support/802.11/linux_sta.php .  (Note for
anyone want to try this with a warm boot from 2.6.32, that this driver
will not compile with 2.6.32 without patching the headers of one of the
blob glue files as one of them fails to include linux/sched.h.)