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Date: Mon, 11 Jan 2010 15:07:23 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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To: "Eric W. Biederman" <ebiederm@xmission.com>
CC: Suresh Siddha <suresh.b.siddha@intel.com>, Ingo Molnar <mingo@elte.hu>,
       Thomas Gleixner <tglx@linutronix.de>, Yinghai Lu <yinghai@kernel.org>,
       "Maciej W. Rozycki" <macro@linux-mips.org>,
       LKML <linux-kernel@vger.kernel.org>
Subject: Re: [patch] x86, apic: use 0x20 for the IRQ_MOVE_CLEANUP_VECTOR instead
 of 0x1f
References: <1263002989.2879.664.camel@sbs-t61.sc.intel.com>	<4B47E7A9.6090904@zytor.com>	<1263250418.2859.681.camel@sbs-t61.sc.intel.com> <m1zl4k8cy7.fsf@fess.ebiederm.org>
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On 01/11/2010 03:00 PM, Eric W. Biederman wrote:
>>
>> In irqinit.c, we statically pre-assign the per-cpu vector to irq
>> mappings (vector_irq) for all the legacy IRQ vectors. Similarly irq_cfg
>> is statically initialized for legacy IRQ's in io_apic.c. So we won't be
>> able to use this space for anything else.
> 
> Last I looked when we switched legacy irqs irqs from pic mode to io_apic mode
> we continue to use the same vector.
> 
> Which means we should not be wasting those vectors and that it is dangerous
> to play lowest priority irq games in that range.
> 

This statement made no sense to me?

	-hpa