[haiku-appserver] Re: haiku MTRR setup

  • From: "Rudolf" <drivers.be-hold@xxxxxxxxxxxx>
  • To: haiku-appserver@xxxxxxxxxxxxx
  • Date: Sun, 14 Nov 2004 20:08:32 +0100 CET

Thanks Axel,

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 :-
)

> 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)

> 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.

> 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.
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.

> 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)

Thanks for responding and setting me straight :-)

Rudolf.


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