Any experience with ThinkPad T420/T520

[Kevin Oberman]

> Sender: Bernhard Schmidt <bschmidt at techwires.net>
> From: Bernhard Schmidt <bschmidt at freebsd.org>
> Date: Tue, 31 May 2011 07:56:19 +0200
> 
> On Monday, May 30, 2011 18:54:31 Kevin Oberman wrote:
> > > Sender: Bernhard Schmidt <bschmidt at techwires.net>
> > > From: Bernhard Schmidt <bschmidt at freebsd.org>
> > > Date: Mon, 30 May 2011 09:15:53 +0200
> > > 
> > > On Sunday, May 29, 2011 18:53:43 Kevin Oberman wrote:
> > > > I'm about to order  new laptop and I am looking at a Lenovo ThinkPad
> > > > T520. Does anyone have experience with this model? Anything that should
> > > > cause alarm? I plan on getting the nVidia 4200N graphics which should
> > > > work with the nVidia driver.
> > > 
> > > What's the current state of "Optimus" support? Last time I've
> > > checked the NVIDIA driver had no support for that so you might
> > > be stuck with the Intel GPU.
> > > 
> > Oops! I typed too quickly. I just found te thread on Optimus support and
> > I'm scanning it now.
> 
> Honestly, I have no clue about the details. The only thing I know
> is that there are 2 ways to switch between GPUs, a real hardware
> switch (which should work on every system) and plain software, which
> didn't last time I've checked, on either Linux or FreeBSD. That
> bothered me quite a bit, decided to buy a "gamer notebook" which
> clearly stated that it has no Optimus therefore.

Bernhard,

I have spent some time researching this and it looks like it is partly
resolved under Linux. (They call it solved, but it's really a kludge
that I would hardly call a final resolution). The "fix" is mostly to
ACPI and very Linux specific, as far as I can tell. Not that doing the
same under FreeBSD would not be possible, but it will take some work by
someone with both more ACPI and graphics knowledge than I have.

I decided to save a few bucks and ordered the T520 without the nVidia...
Just straight Intel which will be pretty limited, too, until the KMS and
GEM work is available. Sigh.

Thanks again for the heads up!
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634
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