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From: jacob pan <jacob.jun.pan@linux.intel.com>
To: ebiederm@xmission.com (Eric W. Biederman)
Cc: Alan Cox <alan@linux.intel.com>,
	Arjan van de Ven <arjan@linux.intel.com>,
	LKML <linux-kernel@vger.kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>, 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: Mon, 7 Jun 2010 22:50:10 -0700	[thread overview]
Message-ID: <20100607225010.342e2fab@jacob-laptop> (raw)
In-Reply-To: <m1631ue5ho.fsf@fess.ebiederm.org>


> > Background:
> > In Moorestown/Medfield platforms, there is no legacy IRQs, all gsis
> > and irqs are one to one mapped, including those < 16. Specifically,
> > IRQ0 and IRQ1 are used for per-cpu timers. So without this patch,
> > IOAPIC pin to IRQ mapping is off by one.
> 
> The patch looks mostly reasonable the comment is wrong.
> 
> 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
> something different on any architecture, but especially not on x86.
> The gsi numbers are firmware specific and you may treat however you
> want.

[jacob pan] If we don't have ISA irqs, why can't we have gsi# = irq#
for the legacy IRQ range? On Moorestown, we are re-using legacy irqs.
e.g. 
sh-4.0# cat /proc/interrupts
          CPU0       CPU1
  0:       1512          0   IO-APIC-edge      apbt0
  1:          0       1482   IO-APIC-edge      apbt1
  9:          0          0   IO-APIC-fasteoi   dw_spi
 10:          0          0   IO-APIC-fasteoi   mrst_i2c
 11:          0          0   IO-APIC-fasteoi   mrst_i2c
 12:          0          0   IO-APIC-fasteoi   mrst_i2c
 23:          0          0   IO-APIC-fasteoi   intel_scu_ipc
 27:         21          0   IO-APIC-fasteoi


  parent reply	other threads:[~2010-06-08  5:50 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-07 23:07 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
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   ` jacob pan [this message]
2010-06-08 19:41     ` [PATCH] x86/sfi: fix ioapic gsi range 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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