From: ebiederm@xmission.com (Eric W. Biederman)
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
Alan Cox <alan@linux.intel.com>,
Arjan van de Ven <arjan@linux.intel.com>,
LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
Feng Tang <feng.tang@intel.com>, Len Brown <len.brown@intel.com>
Subject: Re: [PATCH] x86/sfi: fix ioapic gsi range
Date: Tue, 08 Jun 2010 13:04:15 -0700 [thread overview]
Message-ID: <m1sk4xe1fk.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <4C0E87BB.4050303@zytor.com> (H. Peter Anvin's message of "Tue\, 08 Jun 2010 11\:11\:07 -0700")
"H. Peter Anvin" <hpa@zytor.com> writes:
> On 06/08/2010 01:10 AM, Alan Cox wrote:
>>>> You may not use a 1-1 mapping if you don't have legacy irqs. Linux
>>>> irqs 0-15 are the ISA irqs you may not use those irq numbers for
>>
>> Linux IRQ 0 is "no IRQ assigned", except buried in certain bits of arch
>> specific historical knowledge.
>>
>> Also calling 1-15 ISA IRQ lines is also somewhat misleading given they
>> are almost certainly routing for PCI devices. "PIC IRQ routing" maybe -
>> but even that is not really true on a lot of PC hardware today except by
>> convention.
>
> Yes, but I gather IRQ/GSI 0 is an early-acquire primary timer on MRST on
> Moorestown just as on PC/AT... just a different one. Hence "special" in
> the same sort of way. I don't really care, personally, though.
Right. I have to admit I was stunned when I realized that request_irq
works and has worked for a long time with irq 0. I think that might
actually be a bug. setup_irq is traditionally used for irq 0.
Eric
next prev parent reply other threads:[~2010-06-08 20:04 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-07 23:07 [PATCH] x86/sfi: fix ioapic gsi range Jacob Pan
2010-06-08 0:01 ` jacob pan
2010-06-08 0:24 ` Eric W. Biederman
2010-06-08 0:30 ` H. Peter Anvin
2010-06-08 1:10 ` Eric W. Biederman
2010-06-08 8:10 ` Alan Cox
2010-06-08 18:11 ` H. Peter Anvin
2010-06-08 20:04 ` Eric W. Biederman [this message]
2010-06-08 18:44 ` [PATCH] x86/irq: Rename gsi_end gsi_top, and fix off by one errors Eric W. Biederman
2010-06-09 22:06 ` [tip:x86/urgent] x86, irq: " tip-bot for Eric W. Biederman
2010-06-08 5:50 ` [PATCH] x86/sfi: fix ioapic gsi range jacob pan
2010-06-08 19:41 ` Eric W. Biederman
2010-06-08 19:12 ` Alan Cox
2010-06-08 20:56 ` Yuhong Bao
2010-06-08 22:16 ` Eric W. Biederman
2010-06-08 22:29 ` Alan Cox
2010-06-08 20:36 ` H. Peter Anvin
2010-06-08 20:59 ` Eric W. Biederman
2010-06-08 21:08 ` H. Peter Anvin
2010-06-08 21:51 ` Eric W. Biederman
2010-06-08 20:41 ` jacob pan
2010-06-08 21:22 ` Eric W. Biederman
2010-06-08 22:17 ` jacob pan
2010-06-09 23:44 ` Eric W. Biederman
2010-06-10 8:40 ` jacob pan
2010-06-10 14:39 ` Eric W. Biederman
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