linux-kernel - Re: Via C3/C7: other flags possible ?

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Date:	Sun, 20 May 2007 15:14:38 +0200
From:	Christian Volkmann <haveaniceday@...sv.de>
To:	Claas Langbehn <claas@...tdir.de>
CC:	Simon Arlott <simon@...e.lp0.eu>, linux-kernel@...r.kernel.org,
	Andi Kleen <ak@...e.de>
Subject: Re: Via C3/C7: other flags possible ?

Bit 20 in edx is set if NX is available for C7:

eax in: 0x80000001, eax = 00000000 ebx = 00000000 ecx = 00000000 edx = 00100000
( from your posting "This kernel requires the following..." )

The official VIA Eden  datasheet seems to be NDA. I have not found any
official download link on the pages:
http://www.via.com.tw/en/products/processors/c7/
The /c3/ pages contain the documentation  for the C3 family.

I do not think the NX feature can be switched on/off by regular registers.

May be it helps to play around with the bios ?
Load "default settings" => see how the NX flag acts.
Load "optimized settings" => see how the NX flags acts.

I suppose the bios developer had used one setting to test and
work with the NX flag regular.

Christian


> If you read the other thread properly you'd see that the BIOS has an option to enable or disable it... when enabled it shows up.
PS: @Simon, sorry that I missed the other thread. Too much traffic
and not enough time for me to read all. I suppose that's a fulltime job ;-)

Claas Langbehn wrote:
> Simon Arlott schrieb:
>> On 19/05/07 23:36, Christian Volkmann wrote:
>>> Christian Volkmann wrote:
>>>> Claas asked for the NX flag for the Via C3 (?) processors
>>>> in another thread.
>>
>> If you read the other thread properly you'd see that the BIOS has an
>> option to enable or disable it... when enabled it shows up.
> 
> Right, but my bios disables this after each boot-time :(
> Therefore it would be great if the kernel would not care
> about the BIOS and enable it anyway.
> 
> This seems to be a severe bug in the BIOS, but VIA does not
> deliver a new BIOS since months. :(
> 
>>
>> I can't reboot that box just to test cx8 detection (which is missing).
>>
> It works here.
> 
> 
> 
> claas
> 

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