Re: Using a second display adapter
n Sat, Apr 19, 2008 at 07:53:58AM -0500, Hugo Vanwoerkom wrote:
> Digby Tarvin wrote:
.
.
> >Can anyone explain what happens hardware wise when a second adapter is
> >present? For example, adding a PCI adapter to a system that already
> >has an AGP card.
>
> Just put the second one in xorg. conf:
.
.
> >
> >I assume that video memory for more advanced modes will be mapped to
> >unique addresses by the PCI magic, but arn't the legacy modes like
> >CGA etc tied down to fixed addresses (eg SVGA tex mode to segment b000h)?
> >Is it possible to have have two text mode displays simultaneously?
>
> No. Video of the Linux console is rather primitive. Only the first
> adapter has the VT's.
>
> As soon as X dies you lose the other monitors/keyboards/mice.
Interesting, thanks, but not really what I had in mind on this
occasion.
I am really more interested in the hardware level, not using Linux
Console or xorg driver at all.
By text mode suppert I mean I would like to know if a second adapter
can be configured (via a custom driver) to provide a block of memory
whereby writing one byte the the memory results in one character
displayed on a screen. The same hardware mode used by the linux
console when not in framebuffer mode.
Ideally I would like to be able to tell Linux to keep its hands of
the card so that I can write my own (non X, non glass tty) driver
for it.
Although if the framebuffer driver can be put in text mode then that
might do what I want without needing a new driver. Anyone know?
> I only use Nvidia. Best cards best support although proprietary driver.
Unfortunately I think that probably rules out nVidia for me if I am
looking at writing a custom driver. Details programmers documentation
is probably my highest priority after the basic requirement that it
be able to co-exist with anohter card, with clean/simple interface being
the next priority (eg framebuffer directly addressible without any
indirection).
Perfermance is definately way down the list, as I'm not really planning
in implementing support for fancy acceleration features.
Regards,
DigbyT
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