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

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Message-Id: <200811250745.22487.yuval@avramzon.net>
Date:	Tue, 25 Nov 2008 07:43:22 +0200
From:	Yuval Hager <yuval@...amzon.net>
To:	Larry Finger <Larry.Finger@...inger.net>
Cc:	Michael Buesch <mb@...sch.de>, LKML <linux-kernel@...r.kernel.org>,
	wireless <linux-wireless@...r.kernel.org>,
	bcm43xx-dev@...ts.berlios.de
Subject: Re: BCM4312 Fails when xdm is started

On Monday 24 November 2008, Larry Finger wrote:
> Michael Buesch wrote:
> > On Monday 24 November 2008 09:49:38 Yuval Hager wrote:
> >> * Now check this out - the output of lspci -d 14e4:4312 -x
> >> 02:00.0 Network controller: Broadcom Corporation BCM4312 802.11a/b/g
> >> (rev ff) 00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> >> 10: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> >> 20: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> >> 30: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> >>
> >> (I double checked this)
> >>
> >> huh?
> >
> > Hah, interesting. I think your hardware may be faulty, in fact.
> > To me it really seems like the mainboard has power failures on the PCI
> > bus.
> >
> > This is a laptop, so you can't pull random hardware? Can you run some
> > hardware burn-in tests like mprime (http://mersenne.org/freesoft/) or
> > memtest? If that doesn't help, can you try with another operating system?
>
> I also think you are seeing a hardware failure. Another test to try is
> http://freshmeat.net/projects/cpuburn/?topic_id=146, which will exercise
> the system.
>
> Larry

I can't argue with what the bits mean, but I must say it doesn't "feel" like a 
hardware problem. It is very consistent and deterministic. 

I've been running mprime & burnBX & burnMMX for over 6 hours and it is all 
fine (memtest not ran yet).

However, I have some few interesting findings. 
First, this is totally unrelated to b43, but to the PCI. I get the flawed 1's 
read from lspci even without loading b43.

I played around with different video drivers and the results are:
* If using the 'via' driver, I lose the PCIe card immediately upon 
initialization
* Using the 'openchrome' (trunk version), It works well in the beginning. 
After first blanking the register reads are all 1's, and then when the screen 
is blank I get a different read (some registers are correct, some are wrong), 
and when the screen is unblanked, I get 0xff's again. Very consistent and 
predictabe (same read every time).
* Using the 'vesa' driver I could not recreate the problem. I could not get 
the screen to blank for some reason, but closing the lid, going on 
standby/hibernate, restarting X - all didn't matter much to the PCI and the 
wireless card kept on working.

--yuval

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