Re: [PATCH] Ignore ACPI video devices that aren't present in hardware

[Matthew Garrett <mjg59@srcf.ucam.org>]

On Thu, Jan 17, 2008 at 11:57:11AM +0100, Thomas Renninger wrote:

> Does it make sense to add this as a separate function, searching for a
> physical PCI device for an ACPI device may pop up more often in the
> future? This is a kind of _STA (present or not) function for PCI ACPI
> devices then.

No, I don't think this can be done generically - _ADR for a SATA device 
has a format that looks similar to the one for PCI devices, for 
instance. I think you need to have knowledge of the specific device 
type.

> This has been tested on a Dell 610 only then?
> This sounds like an older machine, I wonder whether the video driver is
> useful on this one at all and whether Windows had to check whether the
> devices are present also...

Also on an HP 2510p. I suspect that the Windows behaviour is to leave 
this up to the graphics driver rather than handling it in the core. 
Toshiba seem to have implemented the complete spec for some time, but 
several other vendors only implemented the section for display output 
switching and obtaining the EDID.

> Please tell me if you have tested more machines, I try to give it a test
> on a Toshiba, Lenovo and whatever I find with a Vista capable BIOS (IMO
> this should be the most important criterion for finding the devices, I
> doubt older Windows Versions made much use of ACPI graphics devices) as
> soon as I find some time...

Yes, I've tested it on some other machines - the HP is the only one I've 
tested with a designed for Vista badge, but it should be correct in 
these cases as well.

-- 
Matthew Garrett | mjg59@srcf.ucam.org