linux-kernel - Re: [PATCH 3/8] PCI/VPD: Add VPD release quirk for Amazon Annapurna Labs host bridge

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Message-ID: <233cb293d7bc572bee5c206732a6f374daa9609e.camel@amazon.com>
Date:   Sun, 14 Jul 2019 15:08:24 +0000
From:   "Chocron, Jonathan" <jonnyc@...zon.com>
To:     "helgaas@...nel.org" <helgaas@...nel.org>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "jingoohan1@...il.com" <jingoohan1@...il.com>,
        "Woodhouse, David" <dwmw@...zon.co.uk>,
        "Hanoch, Uri" <hanochu@...zon.com>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "lorenzo.pieralisi@....com" <lorenzo.pieralisi@....com>,
        "gustavo.pimentel@...opsys.com" <gustavo.pimentel@...opsys.com>,
        "Wasserstrom, Barak" <barakw@...zon.com>,
        "Saidi, Ali" <alisaidi@...zon.com>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "Hawa, Hanna" <hhhawa@...zon.com>,
        "Shenhar, Talel" <talel@...zon.com>,
        "Krupnik, Ronen" <ronenk@...zon.com>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "benh@...nel.crashing.org" <benh@...nel.crashing.org>
Subject: Re: [PATCH 3/8] PCI/VPD: Add VPD release quirk for Amazon Annapurna
 Labs host bridge

On Fri, 2019-07-12 at 08:10 -0500, Bjorn Helgaas wrote:
> On Thu, Jul 11, 2019 at 05:55:56PM +0300, Jonathan Chocron wrote:
> > The Amazon Annapurna Labs pcie host bridge exposes the VPD
> > capability,
> > but there is no actual support for it.
> 
> s/pcie/PCIe/
> s/host bridge/Root Port/
Ack.

> 
> > The reason for not using the already existing quirk_blacklist_vpd()
> > is that, although this fails pci_vpd_read/write, the 'vpd' sysfs
> > entry still exists. When running lspci -vv, for example, this
> > results in the following error:
> > 
> > pcilib: sysfs_read_vpd: read failed: Input/output error
> > 
> > This quirk removes the sysfs entry, which avoids the error print.
> > 
> > Signed-off-by: Jonathan Chocron <jonnyc@...zon.com>
> > ---
> >  drivers/pci/vpd.c | 12 ++++++++++++
> >  1 file changed, 12 insertions(+)
> > 
> > diff --git a/drivers/pci/vpd.c b/drivers/pci/vpd.c
> > index 4963c2e2bd4c..b594b2895ffe 100644
> > --- a/drivers/pci/vpd.c
> > +++ b/drivers/pci/vpd.c
> > @@ -644,4 +644,16 @@ static void quirk_chelsio_extend_vpd(struct
> > pci_dev *dev)
> >  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CHELSIO, PCI_ANY_ID,
> >  			quirk_chelsio_extend_vpd);
> >  
> > +static void quirk_al_vpd_release(struct pci_dev *dev)
> > +{
> > +	if (dev->vpd) {
> > +		pci_vpd_release(dev);
> > +		dev->vpd = NULL;
> > +		pci_warn(dev, FW_BUG "Annapurna Labs pcie quirk -
> > Releasing VPD capability (No support for VPD read/write
> > transactions)\n");
> 
> The "Annapurna Labs pcie quirk" text is superfluous.
> 
Ack.

> > +	}
> > +}
> > +
> > +DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_AMAZON_ANNAPURNA_LABS,
> > 0x0031,
> > +			      PCI_CLASS_BRIDGE_PCI, 8,
> > quirk_al_vpd_release);
> 
> Why DECLARE_PCI_FIXUP_CLASS_FINAL()?  See comments on the MSI-X quirk
> patch.
> 
Responded in the MSI-x quirk patch, but in short, indeed the 0x0031
dev-id is re-used for a non-host bridge device :(

> > +
> >  #endif
> > -- 
> > 2.17.1
> > 
> >