Date:	Fri, 12 Nov 2010 19:06:37 -0500
From:	Jody Bruchon <jody@...ritech.com>
To:	linux-kernel@...r.kernel.org
Subject: ACPI+Inspiron 1545 = crash at xrstor_state()

I previously reported a boot hang on an Inspiron 1545 laptop which is 
cured by disabling CONFIG_ACPI.  I didn't know about the "earlyprintk" 
boot option, and upon using it, I was able to see the actual crash.  
Hopefully the following information will help.  Note that I have turned 
off SMP and APIC/LAPIC support, but the bug persists even with these 
disabled (I noticed a lot of APIC/IO-APIC code that is eliminated in 
early boot if they're disabled.)

The crash was in function xsave_init with EIP at xstate_enable_boot_cpu 
(the last normal message output before this was "Initializing CPU#0").  
To narrow this down further, I edited xsave.c to be full of printk() 
messages for each called function.  The last printk message indicates 
that the function in xsave.c which crashes out is:

xrstor_state(init_xstate_buf, -1);

The result is a general protection fault.  xrstor_state is just a tiny 
piece of asm code, and at this point I've reached the extent of my 
current capabilities, so I don't know where to go from here.  I can 
manually type out chunks of the crash info on request.  I'm clueless as 
to how the inclusion of ACPI causes this.

Please CC my email if you respond since I don't subscribe to LKML.  
Thanks in advance.

Jody Bruchon
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