Date: Sun, 31 Mar 2002 02:12:24 -0800 From: Michael Smith <msmith@freebsd.org> To: Terry Lambert <tlambert2@mindspring.com> Cc: Alfred Perlstein <bright@mu.org>, Michael Smith <msmith@freebsd.org>, scott_long@btc.adaptec.com, mark_salyzyn@adaptec.com, obrien@freebsd.org, current@freebsd.org Subject: Re: asr can not map memory? Message-ID: <200203311012.g2VACOc04299@mass.dis.org> In-Reply-To: Your message of "Sun, 31 Mar 2002 00:27:49 PST." <3CA6C885.AA88C967@mindspring.com>
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> Yeah, you do. I fully understood _that_ context; I think Mike > was talking about other context. It's pretty clear to me that > ranges ought to be per bridge chipset, rather than global... I > thought that that was what the option was working around: that > they were not. I can't imagine how you came to this conclusion. You won't get it from reading the code, or from understanding how PCI works. Maybe you need sleep too. The problem is twofold: - The code is broken, it fails to take into account both prefetched and non-prefetched bridge mappings. It also appears to miscompute the start of one of the attempted range accesses. - There is anecdotal evidence that some bridges pass ranges other than those advertised in their mappings, so even if the first problem is resolved, enforcing correctness may result in occasional lossage. And, since you ask, the whole reason behind having this code in the first place is that we need to be able to correctly assign resources for devices behind bridges. I got run over by a car last time I worked on this code. Time for someone else to pick it up. = Mike -- To announce that there must be no criticism of the president, or that we are to stand by the president, right or wrong, is not only unpatriotic and servile, but is morally treasonable to the American public. - Theodore Roosevelt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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