Re: [Bug 7505] Linux-2.6.18 fails to boot on AMD64 machine

[Ard -kwaak- van Breemen <ard@telegraafnet.nl>]

Hello,
On Thu, Dec 21, 2006 at 04:04:04PM +0800, Zhang, Yanmin wrote:
> I couldn't reproduce it on my EM64T machine. I instrumented function start_kernel and
> didn't find irq was enabled before calling init_IRQ. It'll be better if the reporter could
> instrument function start_kernel to capture which function enables irq.

I can confirm this is a *GENERIC* X86_64 problem:
----
Kernel command line: console=tty0 console=ttyS0,115200 hdb=noprobe root=/dev/md0
init/main.c start_kernel(): interrupts were disabled@525
ide_setup: hdb=noprobe
init/main.c start_kernel(): interrupts were enabled@529
...
start_kernel(): bug: interrupts were enabled early
----
This is on a dell 1950 with a core 2 duo processors.

You have to have ide compiled in, and set ide options to get the irq's enabled,
and then have a setup which will have an irq pending before the irq controller
get's initialized to get the panic. The dell1950 does not panic, the kernel
merely warns.

I am pretty sure the i386 tree has the same problem but I haven't checked yet.
Anyway: the panic is just a way of noticing. The bug is that irq's are enabled
before the irq controller is set up.

But to make the ide_setup/irq bug go away, I think it might be an acceptable
solution to just disable the irq's again after the parse_args, and just to wait
until the SATA tree takes over the IDE tree.

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