Multiple monitors, what to expect.

[devsau]

Haven't tried it yet, but want to later this week. Obviously I use VESA extensions for drawing, since the specific card I use is DX and the windows miniport drivers aren't open sourced (would be too much work and completely pointless to reverse and implement anyways).

The card has a VGA and DVI out, my guess is that the reported resolution from EDID becomes the resolution of the two panes combined together horizontally? Or is it much more work then that?

Thanks

[Combuster]

Expect that you only get to use (and see information about) the screen that showed the bios. You're not going to get multiheaded support with VESA.

[devsau]

Expect that you only get to use (and see information about) the screen that showed the bios. You're not going to get multiheaded support with VESA.

ah okay. I should have expected that. thanks.

[Brendan]

Hi,

Expect that you only get to use (and see information about) the screen that showed the bios. You're not going to get multiheaded support with VESA.

ah okay. I should have expected that. thanks.

What you should expect is that it's similar to having 2 separate video cards, where the circuitry that generates video signals for each monitor is entirely independent. For "legacy VGA/VBE" there's only one set of legacy VGA IO ports which means that VGA/VBE can't handle multiple monitors.

UEFI doesn't have these restrictions. For UEFI, if the firmware has adequate video drivers, there is no reason you can't use UEFI to setup 10 different video cards (or 5 different "dual head" video cards) in 10 different video modes during boot; and end up with 10 different "linear frame buffers" to use for video after boot.

The only other options are to have native video drivers, or to use networking (e.g. maybe thin clients, which are surprisingly cheap second-hand, and are often "PC compatible" and able to boot your OS from network ).


Cheers,

Brendan