[haiku-development] Re: Getting started with Haiku code

  • From: "Axel Dörfler" <axeld@xxxxxxxxxxxxxxxx>
  • To: haiku-development@xxxxxxxxxxxxx
  • Date: Fri, 09 Apr 2010 14:28:38 +0200

Glen <stormbind@xxxxxxxxx> wrote:
> From ../src/add-ons/accelerants/common/create_display_modes.cpp
> 
> I can see that my VDUs' resolutions are not supported in that code,
> and furthermore the ratios differ to the hardcoded modes which appear
> to be established timings. In practice my Haiku display setting allows
> only 1024x600 and this is not supported in the cited code.

For laptop panels, the resolution is read directly from the registers 
on startup (it relies on the BIOS having programmed the correct 
resolution -- this works independently from the resolution you set at 
boot).
In all other cases, it uses EDID information. The common code will just 
fill the missing mode information; if it's exported via EDID already, 
or was programmed by the BIOS it doesn't matter whether or not it's 
part of that list.
In any case, it's all in mode.cpp in the Intel driver.

> Though I have seen the use of blits elsewhere, I have not seen a
> memory allocation for pixel arrays.

Not sure what you mean here.
To get a overview over the graphics driver interface, looking at 
headers/os/add-ons/graphics/Accelerant.h will help. There is also a 
graphics driver test harness in the old BeOS sample code. I've only 
found this old newsletter, though I tought there is more:
http://www.haiku-os.org/legacy-docs/benewsletter/Issue5-15.html#Engineering5-15

Bye,
   Axel.


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