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SubjectRE: [PATCH] PCI/AER: Enable SERR# forwarding in non ACPI flow
Date
> > Currently PCI_BRIDGE_CTL_SERR is being enabled only in ACPI flow.
> > This bit is required for forwarding errors reported by EP devices to
> > upstream device.
> > This patch enables SERR# for Type-1 PCI device.
> >
> > Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>
> > ---
> > drivers/pci/pcie/aer.c | 23 +++++++++++++++++++++++
> > 1 files changed, 23 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c index
> > a2e8838..943e084 100644
> > --- a/drivers/pci/pcie/aer.c
> > +++ b/drivers/pci/pcie/aer.c
> > @@ -343,6 +343,19 @@ int pci_enable_pcie_error_reporting(struct
> > pci_dev
> > *dev)
> > if (!dev->aer_cap)
> > return -EIO;
> >
> > + if (!IS_ENABLED(CONFIG_ACPI) &&
> > + dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
> > + u16 control;
> > +
> > + /*
> > + * A Type-1 PCI bridge will not forward ERR_ messages
> coming
> > + * from an endpoint if SERR# forwarding is not enabled.
> > + */
> > + pci_read_config_word(dev, PCI_BRIDGE_CONTROL,
> &control);
> > + control |= PCI_BRIDGE_CTL_SERR;
> > + pci_write_config_word(dev, PCI_BRIDGE_CONTROL, control);
> > + }
> > +
> > return pcie_capability_set_word(dev, PCI_EXP_DEVCTL,
> > PCI_EXP_AER_FLAGS); }
> > EXPORT_SYMBOL_GPL(pci_enable_pcie_error_reporting);
> > @@ -352,6 +365,16 @@ int pci_disable_pcie_error_reporting(struct
> > pci_dev *dev)
> > if (pcie_aer_get_firmware_first(dev))
> > return -EIO;
> >
> > + if (!IS_ENABLED(CONFIG_ACPI) &&
> > + dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
> > + u16 control;
> > +
> > + /* Clear SERR Forwarding */
> > + pci_read_config_word(dev, PCI_BRIDGE_CONTROL,
> &control);
> > + control &= ~PCI_BRIDGE_CTL_SERR;
> > + pci_write_config_word(dev, PCI_BRIDGE_CONTROL, control);
> > + }
> > +
> > return pcie_capability_clear_word(dev, PCI_EXP_DEVCTL,
> > PCI_EXP_AER_FLAGS);
> > }
>
>
> Should this configuration no be set by Firmware ? why should Linux dictate it
> ?
Hi Oza, Can you please let us know why this should be set by firmware ?
Spec clearly states ERR_CORR,ERR_FATAL/NON FATAL will be forwarded only if this bit is set.
If linux AER service is being enabled without checking/setting this bit, then AER service will
not do anything even ERR_* is seen on link.

Regards,
Bharat

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