Date: Mon, 16 Aug 2010 23:35:44 +0100
From: Chris Vine <chris@cvine.freeserve.co.uk>
To: =?UTF-8?B?R8OhYm9y?= Stefanik <netrolller.3d@gmail.com>
Cc: linux-wireless <linux-wireless@vger.kernel.org>,
	b43-dev <b43-dev@lists.infradead.org>
Subject: Re: [RFT] BCM4312 users with DMA errors, please test!
Message-ID: <20100816233544.40f0e1d4@boulder.homenet>
In-Reply-To: <20100816204154.5100b604@boulder.homenet>
References: <AANLkTimMhW7OX3DT7A3EDNaOnr577KmTv5w9C_mz19TG@mail.gmail.com>
	<20100816204154.5100b604@boulder.homenet>
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Sender: linux-wireless-owner@vger.kernel.org

On Mon, 16 Aug 2010 20:41:54 +0100
Chris Vine <chris@cvine.freeserve.co.uk> wrote:

> On Mon, 16 Aug 2010 19:59:36 +0200
> Gábor Stefanik <netrolller.3d@gmail.com> wrote:
> > Hello Everyone!
> > 
> > If you are experiencing DMA errors on a BCM4312, please test the
> > attached patch. It implements the PCI-E SERDES workaround, which the
> > hybrid driver is applying during early init to LP-PHY cards, and
> > which is a good candidate for the cause of the DMA error.
> > Note that this is not a final patch & it may cause collateral damage
> > for non-4312 cards; if it helps the 4312 problem, I will submit a
> > cleaned-up version.
> 
> This applies to 2.6.35.2, but does not compile:
> 
> drivers/ssb/driver_pcicore.c: In function 'ssb_pcie_mdio_set_block':
> drivers/ssb/driver_pcicore.c:457: error: 'i' undeclared (first use in
> this function) drivers/ssb/driver_pcicore.c:457: error: (Each
> undeclared identifier is reported only once
> drivers/ssb/driver_pcicore.c:457: error: for each function it appears
> in.) drivers/ssb/driver_pcicore.c: In function 'ssb_pcie_mdio_read':
> drivers/ssb/driver_pcicore.c:503: error: expected ';' before
> 'pcicore_write32'
> 
> With the obvious fixes (providing a variable 'i' of int type as the
> count variable and terminating the line which had no terminating
> semi-colon), it compiled OK and the first time I booted up, booted up
> OK but didn't fix the DMA error.  Subsequent attempts to boot up gave
> me a slew of errors on boot up so I am not sure what is going on
> there.
> 
> You might want to check that the obvious fixes to the patch are
> complete.

I have more or less tracked down what is happening.

The first thing to report is that this does not fix the DMA error.

The second thing is that with the patch applied, and with _all_
wireless/ssb modules blacklisted (ssb, b43, wl), if the wl module is
present the kernel bizarrely still tries to load it on boot up and
shortly thereafter hangs with a number of errors reported, which differ
on different boots (there is no particular pattern to them). That in
turn causes some file system corruption which affects further boots
even if the wl module is removed.  The corruption is not that serious
and appears only to affect the kernel image and/or the wl module.
Reinstalling both solved the problem, so far.  ef2fsck -f only reported
that the time stamps were wrong, but inodes and directory structures
were reported as OK.

But caveat testor so far as the corruption is concerned.  I might have
been lucky.

Chris