amd64/138882: Can't install FreeBSD 7.2
avg at freebsd.org
Mon Sep 21 11:54:10 UTC 2009
on 18/09/2009 18:50 Andriy Gapon said the following:
> on 18/09/2009 17:20 Andriy Gapon said the following:
>> I am debugging a somewhat related problem with head code and SB700 ohci.
>> The problem is that certain ports become unusable of there is a keyboard or mouse
>> attached to them during boot.
>> My findings so far:
>> 1) the problem happens only with ports provided by ohci0 (the very first PCI OHCI
>> 2) the problem is that some configuration registers of ohci controller get
>> mysteriously changed after ohci driver configures them and before the first
>> interrupt gets generated by the controller; registers in question are
>> HcControlHeadED and HcDoneHead.
>> Looks like perhaps either the controller doesn't get "sufficiently"
>> reset/re-initialized or firmware/SMM code touches the controller after handover
>> procedure completes.
> My current suspicion is that ohci(4) doesn't clear some memory that it allocates
> for shared use with HC (hardware) and sets a HC register to point to that memory.
> So when HC goes to operation state and examines that memory and sees something
> that looks like valid data, HC uses it and goes bad way.
> But this is just a hypothesis that I've just dreamed up.
> I am going to test it some time later.
This theory turned out to be incorrect, but investigation of it gave some insights
that hopefully should become a basis for a fix.
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