From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ch1ehsobe004.messaging.microsoft.com ([216.32.181.184]:2743 "EHLO ch1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752235Ab2GPPrh (ORCPT ); Mon, 16 Jul 2012 11:47:37 -0400 Message-ID: <50043790.6090605@freescale.com> Date: Mon, 16 Jul 2012 10:47:28 -0500 From: Scott Wood MIME-Version: 1.0 To: Shengzhou Liu CC: , , Subject: Re: [PATCH 1/2 v2] PCI: Add PCI_DEV_FLAGS_USE_NON_MSI_INTX_IRQ to enable non MSI/INTx interrupt References: <1342409487-28256-1-git-send-email-Shengzhou.Liu@freescale.com> In-Reply-To: <1342409487-28256-1-git-send-email-Shengzhou.Liu@freescale.com> Content-Type: text/plain; charset="UTF-8" Sender: linux-pci-owner@vger.kernel.org List-ID: On 07/15/2012 10:31 PM, Shengzhou Liu wrote: > On some platforms, in RC mode, root port has neither MSI/MSI-X nor INTx > interrupt generated, which are available only in EP mode on those platform. > In this case, we try to use other interrupt for port service driver to have > AER, Hot-plug, etc, services to work. > > Signed-off-by: Shengzhou Liu > --- > v2: separated platform-specific part to arch/powerpc/sysdev. > > drivers/pci/pcie/portdrv_core.c | 10 ++++++++-- > drivers/pci/quirks.c | 9 +++++++++ > include/linux/pci.h | 5 +++++ > 3 files changed, 22 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c > index 75915b3..837ad15 100644 > --- a/drivers/pci/pcie/portdrv_core.c > +++ b/drivers/pci/pcie/portdrv_core.c > @@ -212,8 +212,14 @@ static int init_service_irqs(struct pci_dev *dev, int *irqs, int mask) > if (!pcie_port_enable_msix(dev, irqs, mask)) > return 0; > > - /* We're not going to use MSI-X, so try MSI and fall back to INTx */ > - if (!pci_enable_msi(dev) || dev->pin) > + /* > + * We're not going to use MSI-X, so try MSI and fall back to INTx. > + * Eventually, if neither MSI/MSI-X nor INTx available, try other > + * interrupt. (On some platforms, root port doesn't support generating > + * MSI/MSI-X/INTx in RC mode) > + */ > + if (!pci_enable_msi(dev) || dev->pin || ((dev->dev_flags & > + PCI_DEV_FLAGS_USE_NON_MSI_INTX_IRQ) && dev->irq)) > irq = dev->irq; I didn't see a response on the question about what would happen if we did this unconditionally (i.e. just s/dev->pin/dev->irq/ in the original code). We should avoid introducing flags like this unless there's a good reason. Maybe submit a patch that does it unconditionally, and see if that draws a complaint. -Scott