From: Segher Boessenkool <segher@kernel.crashing.org>
To: Geoff Levand <geoffrey.levand@am.sony.com>
Cc: linuxppc-dev <Linuxppc-dev@ozlabs.org>,
Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH] powerpc: Disable external interrupts in bootwrapper
Date: Wed, 28 Mar 2007 18:57:09 +0200 [thread overview]
Message-ID: <a1b0c825d8e7446e1f755e820661b30a@kernel.crashing.org> (raw)
In-Reply-To: <4609BF47.6030306@am.sony.com>
>> Disable external interrupts very early in the bootwrapper in case
>> the firmware left a device generating interrupts.
>
> This is just a guess at what is happening, but I think the OF on my
> G5 uses the timer interrupt as a kind of watchdog timer, so that if
> the loaded code hangs, OF will regain control. If you disable
> interrupts, you may loose this functionality.
Apple OF uses the decrementer to implement all kinds of
alarms. Calling "quiesce" will shut off EE. Shutting
it off manually before that might result in weird behaviour.
Segher
next prev parent reply other threads:[~2007-03-28 16:57 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-27 22:28 [PATCH] powerpc: Disable external interrupts in bootwrapper Mark A. Greer
2007-03-27 23:43 ` Paul Mackerras
2007-03-28 0:12 ` Mark A. Greer
2007-03-28 0:28 ` Benjamin Herrenschmidt
2007-03-28 1:03 ` Mark A. Greer
2007-03-28 1:26 ` David Gibson
2007-03-28 1:34 ` Mark A. Greer
2007-03-28 16:52 ` Segher Boessenkool
2007-03-28 1:05 ` Geoff Levand
2007-03-28 1:34 ` Mark A. Greer
2007-03-28 16:57 ` Segher Boessenkool [this message]
2007-04-10 22:37 ` Mark A. Greer
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