From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:46927) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S6kKU-0005j5-Kn for qemu-devel@nongnu.org; Sun, 11 Mar 2012 11:05:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S6kKS-0005ht-Ru for qemu-devel@nongnu.org; Sun, 11 Mar 2012 11:05:02 -0400 Received: from e28smtp06.in.ibm.com ([122.248.162.6]:36484) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S6kKS-0005hU-7X for qemu-devel@nongnu.org; Sun, 11 Mar 2012 11:05:00 -0400 Received: from /spool/local by e28smtp06.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sun, 11 Mar 2012 20:34:52 +0530 Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q2BF4ode4178096 for ; Sun, 11 Mar 2012 20:34:50 +0530 Received: from d28av02.in.ibm.com (loopback [127.0.0.1]) by d28av02.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q2BKZQoC010865 for ; Mon, 12 Mar 2012 07:35:26 +1100 Message-ID: <4F5CBF0D.3080803@linux.vnet.ibm.com> Date: Sun, 11 Mar 2012 23:04:45 +0800 From: Shu Ming MIME-Version: 1.0 References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] IRQ number, interrupt number, interrupt line & GPIO[in/out] List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Zhi Yong Wu Cc: QEMU Developers IRQ number is actually a word coming from ancient time. When 8259 was popular at that time, we only have 0 ~ 15 interrupts when two 8259 are cascaded. The IRQ number mattered in that time, because 8259 put their vector number in the bus for CPU after the interrupt was delivered. The number did have special meaning to the CPU used as a vector to interrupt table. However, in modern time, especially after we have APIC and MSI, the number don't have much meaning to CPU because the interrupt is targeting some special PCI address to notify the CPU. So APIC don't need put a vector number in the bus. In modern os, it is usually called auto vector for OS to walk the interrupt routine table. Interrupt line is similar to IRQ numbers, interrupt numbers. On 2012-3-2 20:38, Zhi Yong Wu wrote: > HI, > > Can anyone explain their relationship and difference among them? It > is very appreciated if you can make some comments. thanks. > -- Shu Ming IBM China Systems and Technology Laboratory