linux-kernel - Re: BCM4312 Fails when xdm is started

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Date:	Sun, 23 Nov 2008 09:26:25 +0200
From:	Yuval Hager <yuval@...amzon.net>
To:	Michael Buesch <mb@...sch.de>
Cc:	Larry Finger <Larry.Finger@...inger.net>,
	bcm43xx-dev@...ts.berlios.de, LKML <linux-kernel@...r.kernel.org>,
	wireless <linux-wireless@...r.kernel.org>,
	Peter Stuge <peter@...ge.se>
Subject: Re: BCM4312 Fails when xdm is started

On Saturday 22 November 2008, Michael Buesch wrote:
> On Saturday 22 November 2008 16:32:08 Larry Finger wrote:
> > Michael Buesch wrote:
> > > Somebody disabled MMIO and busmastering.
> > > And somebody cleared the CACHE_LINE_SIZE register.
> >
> > Are these all the read/write bits in the configuration area? Should I
> > conclude that someone zeroed this area?
>
> Yeah well. I'm not sure. It _looks_ like someone completely cut the
> physical power line to the card and it reset its complete PCI config.
> So well, X does poke with the PCI devices. But as you said it also happens
> if X doesn't run, I'd rule that out.
> But I would not rule out a fucked BIOS, yet.
> Does the BIOS have any powersave options and/or spread-spectrum options for
> the PCI-bus? Can you try to turn them all off?
> I have a machine that has PCI-slot autodetect and turns of the PCI clock,
> if it doesn't detect a card on that slot. Also turn that off, if you have
> it, too.
>
> > In case the kernel memory diagnostics don't help, is there any way to
> > trap writes to the configuration registers?
>
> Well, if we have random memory corruption, that can hit memory and MMIO.
> It doesn't hurt to turn on all debugging options. Often you get some hint
> by doing so.

I've enabled all CONFIG*DEBUG I could find relevant, and ran the system with:
'debug memory_corruption_check=1 devres.log=1 debug_objects debugpat 
acpi.debug_layer=0x00410002 acpi.debug_level=0xffffffff'
but no hint appears in the logs during the failure.

I did find that certain events recreate the problem immediately. if I 'xset 
dpms force standby' it happens on wakeup. 'xset -dpms' causes this 
immediately as well. If I load X without DPMS support, it still happens after 
the monitor is waken up from (hardware?) blackness.

--yuval

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