Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161209AbWKOTwn (ORCPT ); Wed, 15 Nov 2006 14:52:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161219AbWKOTwn (ORCPT ); Wed, 15 Nov 2006 14:52:43 -0500 Received: from smtp.osdl.org ([65.172.181.4]:28621 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1161209AbWKOTwm (ORCPT ); Wed, 15 Nov 2006 14:52:42 -0500 Date: Wed, 15 Nov 2006 11:49:28 -0800 From: Stephen Hemminger To: Jeff Garzik Cc: Linux Kernel Subject: Re: [PATCH] ALSA: hda-intel - Disable MSI support by default Message-ID: <20061115114928.6ff0936e@freekitty> In-Reply-To: <455B6928.5030202@garzik.org> References: <20061114.192117.112621278.davem@davemloft.net> <455A938A.4060002@garzik.org> <20061114.201549.69019823.davem@davemloft.net> <455A9664.50404@garzik.org> <20061115110953.6cafdef8@freekitty> <455B6928.5030202@garzik.org> Organization: OSDL X-Mailer: Sylpheed-Claws 2.5.0-rc3 (GTK+ 2.10.6; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2302 Lines: 69 On Wed, 15 Nov 2006 14:23:20 -0500 Jeff Garzik wrote: > Stephen Hemminger wrote: > > On Tue, 14 Nov 2006 23:24:04 -0500 > > Jeff Garzik wrote: > > > >> David Miller wrote: > >>> Is this absolutely true? I've never been sure about this point, and I > >>> was rather convinced after reading various documents that once you > >>> program up the MSI registers to start generating MSI this implicitly > >>> disabled INTX and this was even in the PCI specification. > >>> > >>> It would be great to get a definitive answer on this. > >>> > >>> If it is mandatory, perhaps the driver shouldn't be doing it and > >>> rather the PCI layer MSI enabling should. > > > > pci_enable_msi() calls msi_capability_init() and that disables intx > > already. > [...] > > The driver shouldn't deal with this, pci_disable_msi() does. > > Explicit code reference please? > > AFAICS the PCI layer only touched INTx bit for PCI-Express devices. Yeah, why is that? Shouldn't it always be adjusting intx. Are there are any MSI capable devices on non-PCI express? Sorry, don't have PCI spec (costs real $$) to check. --- 2.6.19-rc5.orig/drivers/pci/msi.c 2006-11-15 11:46:23.000000000 -0800 +++ 2.6.19-rc5/drivers/pci/msi.c 2006-11-15 11:46:55.000000000 -0800 @@ -255,10 +255,7 @@ pci_write_config_word(dev, msi_control_reg(pos), control); dev->msix_enabled = 1; } - if (pci_find_capability(dev, PCI_CAP_ID_EXP)) { - /* PCI Express Endpoint device detected */ - pci_intx(dev, 0); /* disable intx */ - } + pci_intx(dev, 0); /* disable intx */ } void disable_msi_mode(struct pci_dev *dev, int pos, int type) @@ -276,10 +273,8 @@ pci_write_config_word(dev, msi_control_reg(pos), control); dev->msix_enabled = 0; } - if (pci_find_capability(dev, PCI_CAP_ID_EXP)) { - /* PCI Express Endpoint device detected */ - pci_intx(dev, 1); /* enable intx */ - } + + pci_intx(dev, 1); /* re-enable intx */ } static int msi_lookup_irq(struct pci_dev *dev, int type) -- Stephen Hemminger - 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/