From mboxrd@z Thu Jan 1 00:00:00 1970 From: Manfred Spraul Subject: Re: MSI interrupts and disable_irq Date: Sat, 13 Oct 2007 11:30:07 +0200 Message-ID: <4710901F.8010206@colorfullife.com> References: <46FC15A9.1070803@nvidia.com> <46FDBCB4.9090802@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Ayaz Abdulla , nedev , Linux Kernel Mailing List , David Miller , Andrew Morton To: Jeff Garzik Return-path: Received: from ev1s-75-125-39-150.ev1servers.net ([75.125.39.150]:40308 "EHLO colorfullife.mysite.adiungo.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1761553AbXJMJae (ORCPT ); Sat, 13 Oct 2007 05:30:34 -0400 In-Reply-To: <46FDBCB4.9090802@pobox.com> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Jeff Garzik wrote: > > I think the scenario you outline is an illustration of the approach's > fragility: disable_irq() is a heavy hammer that originated with INTx, > and it relies on a chip-specific disable method (kernel/irq/manage.c) > that practically guarantees behavior will vary across MSI/INTx/etc. > I checked the code: IRQ_DISABLE is implemented in software, i.e. handle_level_irq() only calls handle_IRQ_event() [and then the nic irq handler] if IRQ_DISABLE is not set. OTHO: The last trace looks as if nv_do_nic_poll() is interrupted by an irq. Perhaps something corrupts dev->irq? The irq is requested with request_irq(np->pci_dev->irq, handler, IRQF_SHARED, dev->name, dev) and disabled with disable_irq_lockdep(dev->irq); Someone around with a MSI capable board? The forcedeth driver does dev->irq = pci_dev->irq in nv_probe(), especially before pci_enable_msi(). Does pci_enable_msi() change pci_dev->irq? Then we would disable the wrong interrupt.... -- Manfred