Date: Sun, 9 Dec 2007 13:33:11 -0800
From: Arjan van de Ven <arjan@infradead.org>
To: Chris Rankin <rankincj@yahoo.com>
Cc: Dan Williams <dcbw@redhat.com>, Andrew Morton <akpm@linux-foundation.org>,
       linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org
Subject: Re: [2.6.23.9] hostap_plx locks up PC when reading PCI I/O memory
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	<587622.50680.qm@web52902.mail.re2.yahoo.com>
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On Sun, 9 Dec 2007 19:41:58 +0000 (GMT)
Chris Rankin <rankincj@yahoo.com> wrote:

> Hi,
> 
> I've recently been having trouble loading the hostap_plx 802.11b
> wireless networking driver, and this evening I managed to narrow the
> problem down to these lines of code by copying code from hostap_plx
> into a "test driver" until the test driver also locked the PC up:
> 
>         /* read CIS; it is in even offsets in the beginning of
> attr_mem */ for (i = 0; i < CIS_MAX_LEN; i++)
>                 cis[i] = readb(attr_mem + 2 * i);
> 
> If I comment these lines out then my test driver just complains about
> the garbage CIS information and fails gracefully. Leave these lines
> in and my PC freezes instantly.
> 
> These lines are part of the prism2_plx_check_cis() function, which is
> called when the module first loads. CIX_MAX_LEN is a #define for 256,
> and cis is a u8* pointer previously allocated as:
> 
> cis = kmalloc(CIS_MAX_LEN, GFP_KERNEL);
> 
> attr_mem is one of the function's paramters, and is defined as void
> __iomem *attr_mem.


can you check if the attr_mem is properly ioremap'd ?
(probably with ioremap_nocache)


>         Region 2: Memory at e8002000 (32-bit, non-prefetchable)
> [size=4K] Region 3: I/O ports at 1080 [size=64]
> 
> so there is apparently 4K of I/O memory at 0xe8002000.
> 
> Can anyone help me understand why my PC is locking up when it
> executes this code, please?

I wonder if there's anything else in that area as well..


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