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DVI on dock available when on Intel integrated chip?
Posted: Fri Nov 28, 2008 4:06 am
by piquadrat
Hi,
I have only Linux on my T400, and can't get the DVI out to work when the discrete graphics chip is deactivated. According to an Intel Linux developer, this is by design, which I find hard to believe, such a huge drawback was not mentioned in any of the many T400 reviews I read before buying the machine.
So, could anybody with a T400, Windows and an advanced minidock please answer this question: Does an external monitor attached to DVI work if the discrete graphics is deactivated in the BIOS?
Thanks in advance,
Benjamin
Posted: Sun Nov 30, 2008 6:01 pm
by awolfe63
Nope.
DVI does not work on integrated graphics. (according to Lenovo - it could be a software thing, but it is probably hardware)
The idea is that if you are docked - why not use the discrete graphics. Pretty Vista-centric.
Posted: Sun Nov 30, 2008 6:04 pm
by awolfe63
Now that I think about it - the Intel chipsets use the same pins for DVI and for PCI-express. This could be the issue - although I'm pretty sure there are desktop motherboards that support both.
Posted: Mon Dec 01, 2008 5:09 am
by dr_st
DVI works for integrated graphics on all T60/T61, and some Z61t laptops. Probably on R61 as well.
I would therefore find it very suprising and disappointing that it wouldn't work on the newer T400/T500.
Posted: Mon Dec 01, 2008 2:29 pm
by awolfe63
Those models don't have a second graphics chip.
Posted: Mon Dec 01, 2008 4:37 pm
by dr_st
Not all the T500 have it either. It could be interesting to see whether behavior is between the GMA-only and the hybrid graphics T400/T500s.
Posted: Mon Dec 01, 2008 4:45 pm
by awolfe63
This is an issue on the models with dual graphics. See the original post. Intel-only machines do DVI on the dock just fine.
Posted: Wed Dec 03, 2008 7:22 am
by piquadrat
That's pretty disappointing, especially because this limitation is not mentioned prominently anywhere. I don't buy the argument that one would use the discrete graphics anyway when docked. I like my laptop as silent as possible, and there is definitely a difference between the two chips in respect to fan speed...
And like awolfe63 said, it's Vista-centric. Switching graphics on Linux does not only involve rebooting, but also replacing a central config file (xorg.conf), completely remove one driver and then install the other one (because AMD's fglrx driver overwrites a couple of libraries with its own versions)...
Posted: Wed Dec 03, 2008 6:55 pm
by lovebeta
I don't know about Linux. But DVI on the dock definitely works under XP/Vista with 4500MHD in T400. Actually you CAN use DVI and VGA concurrently without any problem either.