From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Subject: Re: [PATCH 1/2, pci] pci: Addition of PCI_DEV_FLAGS_QUIET_PCI_REALIGN attribute to the PCI subsystem To: Bjorn Helgaas Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, bhelgaas@google.com, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, ruscur@russell.cc, aik@ozlabs.ru, david@gibson.dropbear.id.au, fbarrat@linux.vnet.ibm.com, brking@linux.vnet.ibm.com References: <20180314163455.15854-1-desnesn@linux.vnet.ibm.com> <20180314163455.15854-2-desnesn@linux.vnet.ibm.com> <20180314180642.GC179719@bhelgaas-glaptop.roam.corp.google.com> From: =?UTF-8?Q?Desnes_Augusto_Nunes_do_Ros=c3=a1rio?= Date: Wed, 14 Mar 2018 15:22:44 -0300 MIME-Version: 1.0 In-Reply-To: <20180314180642.GC179719@bhelgaas-glaptop.roam.corp.google.com> Content-Type: text/plain; charset=utf-8; format=flowed Message-Id: <30c63477-620b-3f8b-82df-fd1e34cd99b8@linux.vnet.ibm.com> List-ID: Hello Bjorn, On 03/14/2018 03:06 PM, Bjorn Helgaas wrote: > On Wed, Mar 14, 2018 at 01:34:54PM -0300, Desnes A. Nunes do Rosario wrote: >> Add PCI_DEV_FLAGS_QUIET_PCI_REALIGN to pci_dev_flags and use it to >> silent PCI realignment messages if the flag is turned on by a driver. >> >> Signed-off-by: Desnes A. Nunes do Rosario >> --- >> drivers/pci/pci.c | 3 ++- >> drivers/pci/setup-res.c | 3 ++- >> include/linux/pci.h | 2 ++ >> 3 files changed, 6 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c >> index 8c71d1a66cdd..be197c944e5f 100644 >> --- a/drivers/pci/pci.c >> +++ b/drivers/pci/pci.c >> @@ -5505,7 +5505,8 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) >> return; >> } >> >> - pci_info(dev, "Disabling memory decoding and releasing memory resources\n"); >> + if (!(dev->dev_flags & PCI_DEV_FLAGS_QUIET_PCI_REALIGN)) >> + pci_info(dev, "Disabling memory decoding and releasing memory resources\n"); >> pci_read_config_word(dev, PCI_COMMAND, &command); >> command &= ~PCI_COMMAND_MEMORY; >> pci_write_config_word(dev, PCI_COMMAND, command); >> diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c >> index 369d48d6c6f1..00a538def763 100644 >> --- a/drivers/pci/setup-res.c >> +++ b/drivers/pci/setup-res.c >> @@ -172,7 +172,8 @@ EXPORT_SYMBOL(pci_claim_resource); >> >> void pci_disable_bridge_window(struct pci_dev *dev) >> { >> - pci_info(dev, "disabling bridge mem windows\n"); >> + if (!(dev->dev_flags & PCI_DEV_FLAGS_QUIET_PCI_REALIGN)) >> + pci_info(dev, "disabling bridge mem windows\n"); > > As far as I'm concerned, we can just remove these messages completely. > I don't think there's any real value there. After I found out that this was happening to all PCI devices on powerpc due to the __weak pcibios_default_alignment() interface (necessary for VFIO passthrough and performance), I confess that this was my first approach to this matter; however I couldn't vouch the need of these messages on other architectures. If there are no further concerns, I definitely prefer sending a second version of this patch only eliminating these messages and attesting the reason why. Thank you very much for your review Bjorn, -- Desnes A. Nunes do Rosário