[haiku-appserver] Re: haiku MTRR setup

  • From: "Axel Dörfler" <axeld@xxxxxxxxxxxxxxxx>
  • To: haiku-appserver@xxxxxxxxxxxxx
  • Date: Sun, 14 Nov 2004 23:58:20 +0100 CET

"Rudolf" <drivers.be-hold@xxxxxxxxxxxx> wrote:
> Stupid of me to point in the direction of app_server. So in my 
> previous 
> message a search and replace should be done for app_server -> kernel 
> :-
> )

Yes, that should do it :)

> > We don't yet support this flag.
> And we also don't have the modules (or whatever is needed) for it I 
> take it then. The kernel itself relies on the system BIOS then about 
> caching setup etc I take it as well. (as it should be according to 
> some 
> Intel spec now read)

Oh, didn't even know about that :-)
I would think that in that case, it might often not even be needed to 
touch these, although it's probably a good idea to make sure that they 
are set up properly, anyway.
And yes, you're right, there are no CPU dependent kernel modules in our 
tree yet.

> > There is no point in publishing these interfaces - they are for 
> > internal kernel use only (and only the kernel loads modules).
> Indeed. If it was published though I could start from there (if I 
> wanted to setup this myself). But it's not. OK.

Yup, I guess you have to live with that. Have you tried reading out the 
MTRR flags to see if they were already setup by the BIOS? Or does BeOS 
reset them some way?

> I was confused because the syslog entries start with 'app_server' (if 
> I 
> remember correctly) if I (kernel graphics driver) request a mapping 
> with MTR flags.

Yes, that's quite confusing, especially with interrupt routines. In the 
syslog, the current running team is printed, and since the app_server 
opens the graphics driver, that output will usually be prefixed with 
[app_server]. For interrupt routines, any thread of any team can run 
which makes this even better :)

> > 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.
> Indeed. I will likely setup a driver for now just modifying/extending 
> the BIOS setup done for the variable range MTRR registers. (found 
> also 
> an example doing this in the R3 days from Be in a newsletter now)

Right, I came across this one, too - that when I heard about MTRR for 
the first time :)

> Thanks for responding and setting me straight :-)

Hm, if I read my post correctly, I couldn't help you that much, though 
;-)

Bye,
   Axel.


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