[haiku] Re: Ang: Re: Preinstalling Haiku on new computers.

  • From: Michael Weirauch <dev@xxxxxxxxxxx>
  • To: haiku@xxxxxxxxxxxxx
  • Date: Wed, 29 Apr 2009 10:50:58 +0200

2009/4/29 Stephan Aßmus <superstippi@xxxxxx>:

> Guys, you are on the wrong track here. As far as I understand, the VESA BIOS
> offers a "mode list", this allows our VESA driver to pick one of these modes
> by it's "index in the list". The VESA BIOS of the graphics card then knows
> how to program and setup the graphics chip to realize this request. As may
> be clear now, it is something completely different for our VESA driver to
> simply select a mode by list id, versus actually programming the graphics
> chip to realize a specific mode. From what I know, it's in theory possible
> to "patch" the VESA BIOS and replace a programmed mode with another mode.
> This requires knowing the location in the BIOS to patch. However it's
> impossible for the driver to actually setup a mode that is not in the list,
> because switching the mode means to select an existing index, _not_
> programming the chip. A VESA driver doesn't know how to do this.

Oh, the joys if ignorance on my side ;)

So it would be up to the haiku_loader to detect other supported modes by
querying the edid info (as we probably have been doing right) and then add
or replace the additional mode in the VESA BIOS so it can be picked up
by the vesa driver for being set?

Thanks for your hints!

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