Date: Tue, 15 Nov 2005 08:58:45 -0500 (EST) From: Andrew Gallatin <gallatin@cs.duke.edu> To: John Baldwin <jhb@freebsd.org> Cc: freebsd-current@freebsd.org Subject: Re: NVidia driver for amd64 / Page Attribute Table status? Message-ID: <17273.59797.727269.288021@grasshopper.cs.duke.edu> In-Reply-To: <200511141153.27640.jhb@freebsd.org> References: <436E66FB.60700@desk.pl> <200511081024.45589.jhb@freebsd.org> <4377216C.8020305@desk.pl> <200511141153.27640.jhb@freebsd.org>
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John Baldwin writes: > On Sunday 13 November 2005 06:20 am, Marcin Koziej wrote: > > Would it be possible for You to put a snapshot patch against CURRENT for > > jhb_pat branch somewhere? I can't make it with P4DB interface, and i > > don't have access to p4. > > > > Best regards, > > m. > > Sure, though it's not commit ready yet. > > http://www.FreeBSD.org/~jhb/patches/pat.patch I have a question about this.. I maintain a driver where our device really, really wants to have its memory mapped write-combined. I currently use mem_range_attr_set() to (try to) do this. The problem is that some BIOSes leave useless uncacheable MTRR attributes laying around which obscure our device (and in fact, nearly all the PCI memory space). In order for the mem_range_attr_set() to work, there cannot be another conflicting MTRR attribute already covering our memory, so we play games with shell scripts which try to remove the uncacheable attributes. This is a royal PITA. With your new PAT stuff, does this mean that I'll no longer have to worry about the MTRR attributes, and I can be certain of getting my memory mapped write-combined? Thanks, Drew
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