hybrid-graphics-linux team mailing list archive

[Michael Reid <kid.meier@xxxxxxxxx>]

> On 06.04.2011 16:30, Albert Vilella wrote:
>> This may be just saying the same with different words, but there are
>> some optimus laptops that have
>> a BIOS "compatible" setting (I've got one), and under such setting,
>> only the nvidia card shows up in Linux and Windows.
>>
>> So there must be an option in these laptops to present the graphics
>> configuration as "only nvidia" to the OS, so that
>> pre-windows7 OSes can see the nvidia card.
>

Yes I also assumed this, and went ahead with my Asus U31J purchase. I
then discovered my assumptions were wrong, and on my particular laptop
there is no such BIOS switch. There is apparently no physical
connection between the Nvidia chip and the display output.

You're right though, in the sense that some Optimus laptops do still
have a so-called "hardware mux", that is enabled/disabled through the
BIOS. It does seem however that some (newer ones especially) have
entirely removed this piece of hardware and the ability to use the
discrete GPU is 100% dependent on appropriate drivers. For now I'm
running on the assumption that if it's not exposed in the BIOS, then
it doesn't have said hardware mux.

I did some digging through my history, this is more or less what I
referenced to come to these conclusions:

Nvidia Whitepaper(s) - http://www.nvidia.com/object/LO_optimus_whitepapers.html
http://forums.nvidia.com/index.php?s=a9ef29ce7505df6a727f5a92b9ccf7d1&showtopic=188184&view=findpost&p=1164718
http://en.wikipedia.org/wiki/Nvidia_Optimus
Referenced by Wikipedia:
http://www.nvnews.net/vbulletin/showpost.php?s=804c18be75c445d7539dd3525d49a237&p=2291824&postcount=3

/mike.


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