[ltp] Re: T520 Ubuntu 11.10 x64 - can't connect external monitor

Micha linux-thinkpad@linux-thinkpad.org
Sun, 05 Feb 2012 22:37:28 +0200

I've got the version with the Quadro 2000M actually.

As for external displays, I've been able to run both (although with
discrete graphics only two at a time, so if both external displays are
connected I need to disable internal display).

To run with NVIDIA I installed the proprietary NVIDIA drivers (I use the
latop for CUDA so no open drivers). I than ran nvidia-xconfig to
generate the xorg.conf (and disabled the keyboard and mouse sections to
let them configure automatically). I also had to set X to use the NVIDIA
drivers. I use debian unstable with the NVIDIA packages us that means to
run update-alternatives --config glx (although nvidia is the default glx
once the packages are installed). The NVIDIA driver is not compatible
though with xrandr, so I enable external displays via nvidia-settings.

I tried connecting external displays in internal mode (via Intel), but
it just made the kernel go haywire.

As for memory, it's not a video memory issue to drive two HD displays. A
full HD display is 1920x1080x4 (RGBA format) which means you need ~8MB
per display. If you want double buffering that's 16MB. Not sure how much
the NVS 4200M has, but I did just fine at the time with an NVS 140M that
has only 128MB of ram with two displays.

With the w520, the external connectors on the laptop are connected
directly to the NVIDIA so the intel can't drive them, only NVIDIA. There
are external connectors connected to the intel via the docking station
if you have it.

Never tried nouveau so I don't know how to set it up or whether it has
access to the external connectors (it's not an option for me as like I
said, I need this laptop for CUDA which it doesn't support). Never tried
bumblebee either I'm afraid, seemed too much of a hassle at the moment,
so can't report on that as well.

Trying to work with displaylink at the moment to get an external display
running (due to other reasons), but only managed to get it running via
the framebuffer driver with acceleration and internal screen disabled,
but that is a whole different story.

On 05/02/2012 22:20, Fen Labalme wrote:
> Hi Micha -
> Thanks for the thought.
> You wrote:
>     See if you can set the laptop to discrete mode rather than optimus and
>     then run both the internal and external displays off the nvidia gpu.
> Do you hook your external display up via the DisplayPort (or DVI)?  Will
> the discrete graphics drive e.g. a projector hooked up to the VGA port?
>  I could get the NVIDIA card to run the T520 just fine, but was not able
> to get it to push bits to the DisplayPort or the VGA.  Did you need to
> tweak anything in the xorg.conf or anywhere else?
>     That is what I do with my w520.
> It looks like the w520 comes with the NVIDIA Quadro 1000M Graphics with
> 2GB DDR3 Memory, so that may be able to handle driving larger displays.
> When driving via Intel Integrated graphics: xrandr puts the max at
> 8192x8192, I've not been able to go beyond 3200x1200 which is just shy
> of the reported <http://www.nvidia.com/object/nvs_techspecs.html>
> 4,096,000 reported max resolution of my card.
> Thanks again!
> =Fen
> System specs:
> T520 with i7-2760QM running Ubuntu 11.10
>    Intel HD 3000 Integrated GPU
>    NVIDIA NVS 4200M w/ Optimus with 1GB DDR3 Memory
> Thinkpad monitor has 1600x1200 display (HD+)
> Samsung monitor has 1920x1200 display