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From: ebiederm@xmission.com (Eric W. Biederman)
To: Yinghai Lu <yinghai@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>
Subject: Re: oops in ioapic_write_entry
Date: Tue, 03 Aug 2010 01:00:46 -0700	[thread overview]
Message-ID: <m11vagw2fl.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <4C57C319.8070800@kernel.org> (Yinghai Lu's message of "Tue\, 03 Aug 2010 00\:19\:53 -0700")

Yinghai Lu <yinghai@kernel.org> writes:

>>> Index: linux-2.6/arch/x86/kernel/apic/io_apic.c
>>> ===================================================================
>>> --- linux-2.6.orig/arch/x86/kernel/apic/io_apic.c
>>> +++ linux-2.6/arch/x86/kernel/apic/io_apic.c
>>> @@ -1029,10 +1029,7 @@ static int pin_2_irq(int idx, int apic,
>>>  	} else {
>>>  		u32 gsi = mp_gsi_routing[apic].gsi_base + pin;
>>>  
>>> -		if (gsi >= NR_IRQS_LEGACY)
>>> -			irq = gsi;
>>> -		else
>>> -			irq = gsi_top + gsi;
>>> +		irq = gsi_to_irq(gsi);
>>>  	}
>>>  
>>>  #ifdef CONFIG_X86_32
>
> what is the point for making irq = gsi_top + gsi when mptable is used instead of acpi?

Because it is only convention that when mptables are used that the
first apic pins 0-15 are the ISA irqs.  This thread witnessed and a
pci irq that came in pin < 16 that was not an ISA irq.  The truly rare
and exotic case would be for the ISA irqs to be outside the first 16
ioapic pins but the es7000 did exactly that.

Eric

  reply	other threads:[~2010-08-03  8:00 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-02  5:28 oops in ioapic_write_entry Dave Airlie
2010-08-02  6:49 ` Yinghai Lu
2010-08-02 23:17   ` Dave Airlie
2010-08-03  1:32     ` Yinghai Lu
2010-08-03  1:34       ` Yinghai Lu
2010-08-03  3:13         ` Eric W. Biederman
2010-08-03  7:19           ` Yinghai Lu
2010-08-03  8:00             ` Eric W. Biederman [this message]
2010-08-03  8:04               ` Yinghai Lu
2010-08-03  8:56                 ` Eric W. Biederman
2010-08-03  9:01                   ` Yinghai Lu
2010-08-03  9:15                     ` Eric W. Biederman
2010-08-03  9:36                       ` Yinghai Lu
2010-08-03 11:08                         ` Eric W. Biederman
2010-08-03 19:45                           ` Yinghai Lu
2010-08-03 20:02                             ` Yinghai Lu
2010-08-03 21:38                             ` Eric W. Biederman
2010-08-03 23:12                               ` Dave Airlie
2010-08-04  0:00                               ` Yinghai Lu
2010-08-04  1:19                                 ` Eric W. Biederman
2010-08-04  7:33                               ` Ingo Molnar
2010-08-04  8:59                               ` Yinghai Lu
2010-08-04  9:26                                 ` Ingo Molnar
2010-08-04 12:12                                 ` Eric W. Biederman
2010-08-04 19:22                                   ` Yinghai Lu
2010-08-04 20:34                                     ` Eric W. Biederman
2010-08-04 22:06                                       ` Yinghai Lu
2010-08-03  8:00             ` Yinghai Lu
2010-08-03  8:27               ` Eric W. Biederman
2010-08-03  3:26     ` Eric W. Biederman
     [not found]       ` <AANLkTi=qtLkY0=h77=EVL+y1q41b_cMBODvL4Hu6A6wL@mail.gmail.com>
2010-08-03  6:00         ` Eric W. Biederman

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