I have a system with two video cards, one I care about, and one I don't care about at all. I'd really like to disable the one I don't care about.

I am working in CentOS 5.11 which is...based on RedHat 5.11 if that helps. I'm thinking something can be done with the X configuration, but I'm not sure what that would be.

Have you checked BIOS settings? There may be an option. You can blacklist the concerned video card kernel module.

And why not remove one of them physically.

Hi...

If you're able and it's not a discrete or hybrid graphics sort of set up, I would agree this is probably the easiest way.

Regards...

For the older legacy rhel5

in your xorg.conf you have 2 cards set up
just disable the one in that file

-- for nvidia

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Brilliant! there we go, and sorry for the confusion, one of the video "cards" is on-board, and thus can't be removed, incidentally it's the one I don't want. Additionally, there's no BIOS setting that I can find to disable the on-board video. Oddly enough, my system is smart enough to push primary video output to whatever secondary card it finds at the pre-boot level.

JohnVV-

Thank you, by "disable" do you mean delete the device section for that card in the configuration?

I wouldn't delete the section, but just comment it out. Also, be aware that some built-in cards are the 'default' for booting/BIOS/console output, so when you fire that machine up, it may use the first one it finds as your console. Which may or may not be an issue.

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Please, stop posting things that are misleading or incorrect. I have NEVER seen a machine so far that has an option to disable a video card in the system BIOS. And giving the advice to blacklist the video card module is plain bad...especially since you never asked if both of the cards have the same chipset. If they're both nVidia cards, and you blacklist the nvidia module, what do you think will happen????
Because that's not what the OP asked, and not what they want to do.

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So you find that out by magic without OP saying it.

That also by magic.

This link on arch may help atleast the generic part.

No, I find that out by READING AND UNDERSTANDING what the OP said. Very first post..."I'd really like to disable the one I don't care about." See the word "disable"?? That means DISABLE...not REMOVE.
No, that's pointing out the bad advice you gave. You didn't ask ANYTHING about the cards, and just blindly telling someone to blacklist a module without knowing ANYTHING about that module/hardware/system is NOT A GOOD THING. Again, you didn't (and DON'T) have enough information to even suggest that.
Nope, not at all, since that deals with Arch Linux (the OP has CentOS), and hybrid graphics (which the OP doesn't have). So NONE of that applies.

Again, PLEASE STOP posting misleading/incorrect/incomplete/potentially damaging advice. Pay attention to what the OP is saying and asking.

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Are you sure it isn't disabled? Most BIOS's I have used default to disabling the on-board video when there is also an external card.

I typically use lspci to find out which video is enabled.

On the main question, I used to understand these things in the old days when the info unconditionally came from the xorg.conf file and your choice was leave an automatically generated xorg.conf alone or edit it. Either way, you could look at it and know what was there.

So far as I understand, you can still override things by creating an xorg.conf, but its mere existence does not prevent defaults from coming from other places that I don't understand. If some aspect is undefined in xorg.conf, I don't really understand where the defaults come from. I don't know how you find out what the defaults were if you want to tweak them rather than reinvent whole cloth. I don't know what you need to put in xorg.conf to really suppress some defaults vs. just supplement them.

Maybe Centos 5 is what I was describing as those "old days". So what you see in xorg.conf is what X is actually using. My memory isn't perfect and I have tweaked quite a lot of problem video set ups since the last time I did so for Centos 5.

Back at you.

So you are looking at a very different pool of machines than I have looked at. Your experience is far short of universal.

That was far from clear to me. You may be reading the OP's mind better than I am (or worse).

Every desktop system I've seen with onboard video has had some means of disabling that in the BIOS. Sometimes it's buried a bit in the setup screens (Setup -> Advanced -> Internal Graphics Configuration -> Internal Grahics Mode : Disabled), but it's always been there. My laptops don't have that, but they have no provision for adding a video card either, so what would be the point?

There is ample documentation about the new X configuration process which can clear things up for you.
http://www.x.org/releases/X11R7.7/do...g.conf.5.xhtml
And where does this come from? Why???
I never said my experience was 'universal'...just said what I have seen. I've got several machines at the house, and NONE of them have any BIOS options to disable the built-in video.
I'm reading what the OP SAID...which is "I have a system with two video cards", along with "one of the video "cards" is on-board"..meaning the second one IS NOT on board. Hybrid systems share a good bit of hardware, and have to be integrated with each other on a hardware level.

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I'm not disputing that it could be there..just that I've not seen it. Maybe because I haven't looked in the right place, too, or that the systems I've used haven't had on-board graphics. Since I deal with mostly server-type machines (most don't even HAVE monitors, and many are blades), that's certainly a possibility.

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