Date: Mon, 4 Jun 2007 11:19:25 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-acpi@freebsd.org Subject: Re: Computer hangs on reboot Message-ID: <200706041119.26958.jhb@freebsd.org> In-Reply-To: <24393ae80706012112he0e2a96x1e0da9e8f5f6d1b0@mail.gmail.com> References: <24393ae80705172026u6194f11esc525d52470aa71f9@mail.gmail.com> <24393ae80705290916i7962bfaak62ea867494d2e77b@mail.gmail.com> <24393ae80706012112he0e2a96x1e0da9e8f5f6d1b0@mail.gmail.com>
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On Saturday 02 June 2007 12:12:14 am Andrey Shuvikov wrote:
> On 5/29/07, Andrey Shuvikov <mr.hyro@gmail.com> wrote:
> > On 5/29/07, John Baldwin <jhb@freebsd.org> wrote:
> > > On Saturday 26 May 2007 01:14:52 pm Andrey Shuvikov wrote:
> > > > I tried to add some debug output to cpu_reset_real() code:
> > > >
> > > > printf("cpu_reset_real(): before keyboard reset\n");
> > > > outb(IO_KBD + 4, 0xFE);
> > > > printf("cpu_reset_real(): after keyboard reset\n");
> > > >
> > > > The last two lines I see on the screen when I try to reboot are:
> > > >
> > > > cpu_reset_real(): before keyboard reset
> > > > c
> > > >
> > > > So the computer is halted but doesn't go to reboot.
> > >
> > > So what if you disable the keyboard reset and let the other methods
happen?
> > >
> > > --
> > > John Baldwin
> > >
> >
> > I tried to set BROKEN_KEYBOARD_RESET option but nothing changed
> > (except that I didn't see these debugging messages, obviously). Is it
> > possible that keyboard controller issues the reset signal but the CPU
> > waits for something? Or reset pin is disabled somehow?
> >
>
> Tried to investigate further... Added code to print keyboard
> controller output port to make sure A20 is open. Got 0x0B. Does it
> mean that A20 is really open? If A20 is controlled by some kind of
> "Fast A20" option, will keyboard controller still show the right
> status? And what else can I check?
I believe I/O port 0x92 can gate A20 as well, and that it is only open if both
say it is open. Grab a datasheet for an ICH from developer.intel.com to find
more details on port 0x92.
--
John Baldwin
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