[haiku-appserver] Re: haiku MTRR setup

  • From: "Axel Dörfler" <axeld@xxxxxxxxxxxxxxxx>
  • To: haiku-appserver@xxxxxxxxxxxxx
  • Date: Sun, 14 Nov 2004 19:48:07 +0100 CET

"Rudolf" <drivers.be-hold@xxxxxxxxxxxx> wrote:
> I might be in the wrong place here, but what's known on the Haiku 
> MTRR 
> features setup? Do we have something yet?

We don't yet support this flag.

> For instance: Dano/Zeta has modules for this in a folder named 'cpu/' 
> somewhere (loaded by the app_server AFAIK). There is a general 
> module, 
> and three submodules for Intel, AMD and another manufacturor. R5 
> seems 
> to have a app_Server internal solution(?)
> [...]
> I think Be never published the interface to the MTR module(s) as it's 
> only in Dano officially.

There is no point in publishing these interfaces - they are for 
internal kernel use only (and only the kernel loads modules).
Under BeOS it works like this: you specify the B_MTR_* flags (as 
specified in KernelExport.h) as flag when creating the area. The kernel 
will load the correct CPU module for you at boot time, and mark the 
area as write combined or whatever you ask for using that module.
There is no need to involve the app_server into this, only the graphics 
driver has to take care for this flag when creating the frame buffer 
area.

If you need to duplicate that behaviour on existing BeOS, you would 
indeed need to find out the private module interface used there, but 
for Haiku, we're free to chose our own.

Bye,
   Axel.


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