Monitor Detection via DDC

[Matthew Garrett]

On Thu, Aug 17, 2006 at 04:50:00PM +0100, Martin Owens wrote:

> Has anyone else looked at the area of functionality? I know HAL normaly deals
> with auto detection but getting DDCcontrol using hal might be an excelent way
> of increasing the abilities of HAL, obviously I could do with some kind of
> detection for my hardware project.

Various issues:

1) As pointed out, to get basic VESA DDC to work, you'll need an x86 
emulator or to do stuff via lrmi.
2) Lots of hardware doesn't do DDC (say, approximately every laptop).
3) On a lot of hardware, DDC only works properly if you know how to 
drive the i2c hardware on the video card yourself.

So you're basically talking about a requirement for large chunks of 
every graphics driver in X, plus x86emu for every architecture other 
than x86. And, even then, there's a lot of hardware that it won't work 
on - X knows how to get screen resolutions via mechanisms other than DDC 
for laptops, for instance.

It's a cute idea, but, to be honest, I think you'd be better either 
extending X to add the information to HAL itself, or working on 
splitting X up so that hardware probing is done by logically separate 
components. That way we'd get the benefit of the probing not being 
limited to X without having insane quantities of code duplication.
-- 
Matthew Garrett | mjg59 at srcf.ucam.org