Thank you for the reply. I also found contigmalloc() shortly after I posted the original question (what an embarrassment ;-p), then met another restriction: Because these memory regions are to be accessed by a userland process (X server), they have to be somehow mapped into the user space. So far it seems I would have to do something similar to vm_mmap(), but I'm not sure if this is a right direction. Do you have any suggestions?
Cheers, Eugene On Tue, Oct 09, 2001 at 07:37:41PM -0500, Jonathan Lemon wrote: > > > In article <local.mail.freebsd-hackers/[EMAIL PROTECTED]> you >write: > >What would be the best way to allocate: > > > >1) a VM page whose physical address falls within a certain boundary, and > >2) a VM object whose pages are contiguous in physical address space? > > > >Background: > >The !@*%^*!&#^%*&!#^$!@ Intel 810/815 graphics controller requires its > >instruction and hardware cursor buffers to reside within first 32MB and > >512MB of *physical* memory space respectively. :( :( ;( The XFree86 > >driver assumes the Linux memory model (virtual addr == physical addr), > >so it runs on Linux, but not always on FreeBSD. > > You probably want contigmalloc(), which allocates a range of memory > which is physically contiguous. (assuming this is a in-kernel driver) > > void * > contigmalloc( > unsigned long size, /* should be size_t here and for malloc() */ > struct malloc_type *type, > int flags, > unsigned long low, > unsigned long high, > unsigned long alignment, > unsigned long boundary) > > -- > Jonathan To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message