Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752184AbbETDMn (ORCPT ); Tue, 19 May 2015 23:12:43 -0400 Received: from mga02.intel.com ([134.134.136.20]:17023 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751903AbbETDMk (ORCPT ); Tue, 19 May 2015 23:12:40 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,462,1427785200"; d="scan'208";a="574015048" Message-ID: <555BFB95.30208@linux.intel.com> Date: Wed, 20 May 2015 11:12:21 +0800 From: Jiang Liu Organization: Intel User-Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Bjorn Helgaas CC: Thomas Gleixner , "Rafael J . Wysocki" , Lv Zheng , LKML , linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, "x86 @ kernel . org" Subject: Re: [RFC 2/4] PCI, MSI: Optionally free legacy PCI IRQ when enabling MSI/MSI-X References: <1430968374-29286-1-git-send-email-jiang.liu@linux.intel.com> <1430968374-29286-3-git-send-email-jiang.liu@linux.intel.com> <20150519213937.GR31666@google.com> In-Reply-To: <20150519213937.GR31666@google.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1291 Lines: 28 On 2015/5/20 5:39, Bjorn Helgaas wrote: > On Thu, May 07, 2015 at 11:12:52AM +0800, Jiang Liu wrote: >> Once PCI MSI/MSI-X is enabled by the device driver, PCI device won't >> make use of legacy PCI IRQ until PCI MSI/MSI-X is disabled again. >> So optionally free legacy PCI IRQ when enabling MSI/MSI-X and reallocate >> when disabling MSI/MSI-X. > > The rest of this series makes sense to me. If you want to remove an > IOAPIC, you want to make sure all of the IRQs using that IOAPIC have been > freed. > > But I'm trying to figure out this patch. Do you want to free the IRQ when > enabling MSI because it enables you to remove the IOAPIC without removing > the device? That wouldn't really make sense to me because then the device > has no possibility of using INTx. Hi Bjorn Sorry for the confusion. This patch is not for IOAPIC hot-removal, but it's an effort to use IRQ resource precisely. The idea is to allocate IRQ resource on demand and release it when not used. We could skip this patch if it's not worth the cost. Thanks! Gerry -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/