Date: Wed, 14 Oct 2009 16:45:25 -0400 From: John Baldwin <jhb@freebsd.org> To: Marcel Moolenaar <xcllnt@mac.com> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Warner Losh <imp@bsdimp.com> Subject: Re: svn commit: r197969 - head/sys/conf Message-ID: <200910141645.26010.jhb@freebsd.org> In-Reply-To: <2D55EFED-675A-4CC7-AF39-DE83961552F0@mac.com> References: <EC2B1366-67F5-4021-A5A0-040D035ADD6C@mac.com> <20091014.113945.74724941.imp@bsdimp.com> <2D55EFED-675A-4CC7-AF39-DE83961552F0@mac.com>
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On Wednesday 14 October 2009 2:35:16 pm Marcel Moolenaar wrote: > On Oct 14, 2009, at 10:39 AM, Warner Losh wrote: > > > > I can't be more clear than this. You keep ignoring me, and it is very > > frustrating. > > I'm not ignoring you. I'm still talking. You simply haven't convinced > me. While it's possible (likely?) that I don't understand the issues, > all you've achieved so far is that I'm more convinced that limiting > orm(4) to i386 and amd64 is the right thing, because the alternative > is not at all appealing. > > > The problem is that the > > powerpc and itanium isa modules allow memory ranges that shouldn't be > > allowed. That's the platform specific code that needs to be fixed. > > isa_set_resource() is MI code and it happily adds whatever resources > a driver wants. The only chance MD code has is to fail the allocation, > but since the whole ISA code bypasses the newbus hierarchy, there's > no way we know in the isa MD code what is valid and what isn't unless > we add kluges to platform code. > > If you want to fix it for real, does that mean fix it for real or > does that mean add kluges to platform code? > > Shouldn't we have ISA bridges obtain the set of valid resources > from their parent in the newbus hierarchy? Hmm, can we even know that? PCI-ISA bridges in x86 at least don't have any I/O limit registers like PCI-PCI bridges, instead they are subtractively decoded, i.e. they "eat" any memory request that no one else claims. I'm not sure if other platforms have a way of knowing this however. Are you aware of something in OFW to communicate this? ACPI does this for Host-PCI bridges via ResourceProvider() resource entries, but I've never seen ACPI do it for a PCI-ISA bridge. -- John Baldwin
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