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SubjectRe: [PATCH 1/2, pci] pci: Addition of PCI_DEV_FLAGS_QUIET_PCI_REALIGN attribute to the PCI subsystem
On Wed, Mar 14, 2018 at 03:22:44PM -0300, Desnes Augusto Nunes do Rosário wrote:
> 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 <desnesn@linux.vnet.ibm.com>
> > > ---
> > > 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,

No problem, welcome to PCI, and I hope we see more of your work!

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