How and which part of PC decide which display output to use (vga,hdmi,dvi) ?

For now I will assume the graphics card decides which output to use.

How it does this is unknown to me. Does anybody have some references/docume ntation ?

I am particularly interested in nvidia's GT 520.

I believe this device works as follows:

  1. If an HDMI cable is connected it will try to use it.

However this procedure overlooks the possibility that HDMI is only used for AUDIO connection and thus this procedure is flawed.

  1. If an HDMI cable is connected by the HDMI device is off it might assume the monitor is off or it will probably use the DVI output.

  1. Only if HDMI cable is disconnected and possibility DVI cables will it fa ll-back to VGA output.

So basically as far as I know it's impossible to instruct the GT 520 to alw ays use the VGA output ?!?

It seems this graphics card has some "auto-detect" logic which in my case i s flawed and does not do what I want.

I want it to always use VGA, but do enable HDMI audio.

It is possible to boot as follows though, a re-boot is required, pulling ou t the hdmi cable will not fall back to VGA.

Boot process:

  1. Attach VGA cable only.
  2. After boot is complete attach HDMI cable, make sure HDMI device is off.

This is ofcourse a bit risky to do this every time.

The BIOS has no option to select which display output to use.

To me it's clear this is a short coming in the design of these electronics.

I do not know if newer hardware/bioses/uefis and such have selection/guis t o configure which output to use.

In case HDMI was auto-selected then using an HDMI monitor or HDMI-to-vga c able does offer some possibilities of getting GUI back on monitor though it looks very weird... scan line issues.

But it's clear enough to re-boot the computer and pull out the hdmi cable a nd re-attach vga-cable to system.

It's clear to me that this setup of using GT 520 for VGA and HDMI audio is not a viable solution and only viable for experimenting with nvidia's audio driver, which I suspect might have an audio-channel swapping issue with SL /SUB or it's my receiver, maybe later though.

Quite a weird experience this auto-display-selection tech failing.

If you like weird electronics behaviour this one tops many others =D and I highly recommend you try it out to get that x-files feeling ! =D

(Is there a way to force VGA on GT 520 ?)

Part 2:

Damn, I forgot to test out DVI-FULL to VGA + HDMI AUDIO.

I forgot I have these DVI-TO-VGA cables and I forgot the GT 520 has DVI-FUL L.

I should have tried that out... but the main problem was the NVIDIA drivers failed to install properly.

Could also be a windows 7 issue, perhaps same as with creative drivers.

Hope not.

So I pulled out the GT 520 and replaced it with GT 1030.

I will now download latest GT 1030 driver and try to install that.

Kinda suxxx... how the older nvidia driver failed to install... this kinda ruined my audio experiments...

I might have thought of the DVI option or maybe not.

But at least now I write this note to myself to perhaps try this experiment in the future.

For now I have no idea what would happen if the following situation occurs:

  1. VGA monitor connected to GT 520 via DVI-to-VGA cable.
  2. Receiver connected to GT 520 via HDMI cable for audio only.

Which devices would the GT 520 prefer ?

The fake-DVI or the somewhat-fake-Receiver (since it's only hdmi-audio) ?!?

Though graphics card doesn't know it's only half a receiver lol.. doesn't e ven know it's a receiver, graphics card thinks it's a monitor =D

Perhaps some day in the future when I do a fresh install of windows 7 or ma ybe XP I will re-try this experiment.

For now I am not doing it cause I have no idea how to get the drivers worki ng again.

After reboot the driver complaints that some Wizard is already running.

Perhaps it's adobe reader service/startup crap/check that causes it... so I have disabled that for now.

Bye for now, Skybuck.

Reply to
skybuck2000
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There's a VESA standard (but it costs big money to get a copy of it) that specifies how the monitor identifies itself to an attached video card. The video card driver chooses among the display modes offered, and can be overridden (if you can find the right control panel).

Reply to
whit3rd

whit3rd wrote in news: snipped-for-privacy@googlegroups.com:

SOME old, and almost ALL newer video cards, and likely certainly any that are HDMI have multiple output ports and the connected device gets recognized and used, until a second is attached, then various means are used to provide a user dialog to select one or both of the connected devices to be active and how to do so, by clone or split, etc.

Reply to
DecadentLinuxUserNumeroUno

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