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Documentation: PCI: Drop recommendation to configure AER Capability 

Since f26e58bf6f ("PCI/AER: Enable error reporting when AER is native"),
the PCI core enables PCIe device error reporting for all devices during
enumeration, so drivers don't need to do it.

Remove the recommendation for drivers to configure AER and call
pci_enable_pcie_error_reporting() themselves.

Also remove the suggestion that drivers may change AER mask and severity
registers.  Ownership of these registers is negotiated between the OS and
platform firmware.  If firmware owns these registers, the OS must not
change them.

Link: https://lore.kernel.org/r/20230609222500.1267795-3-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
This commit is contained in:
Bjorn Helgaas 2023-06-09 17:24:58 -05:00
parent ba3da66783
commit a6378a7a1c
1 changed files with 2 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

56
Documentation/PCI/pcieaer-howto.rst
View File

@ -96,8 +96,8 @@ Documentation/ABI/testing/sysfs-bus-pci-devices-aer_stats
Developer Guide
===============
To enable AER aware support requires a software driver to configure
the AER capability structure within its device and to provide callbacks.
To enable AER aware support requires a software driver to provide
callbacks.
To support AER better, developers need understand how AER does work
firstly.
@ -135,15 +135,6 @@ hierarchy and links. These errors do not include any device specific
errors because device specific errors will still get sent directly to
the device driver.
Configure the AER capability structure
--------------------------------------
AER aware drivers of PCI Express component need change the device
control registers to enable AER. They also could change AER registers,
including mask and severity registers. Helper function
pci_enable_pcie_error_reporting could be used to enable AER. See
section 3.3.
Provide callbacks
-----------------
@ -212,31 +203,6 @@ to reset the link. If error_detected returns PCI_ERS_RESULT_CAN_RECOVER
and reset_link returns PCI_ERS_RESULT_RECOVERED, the error handling goes
to mmio_enabled.
helper functions
----------------
::
int pci_enable_pcie_error_reporting(struct pci_dev *dev);
pci_enable_pcie_error_reporting enables the device to send error
messages to root port when an error is detected. Note that devices
don't enable the error reporting by default, so device drivers need
call this function to enable it.
::
int pci_disable_pcie_error_reporting(struct pci_dev *dev);
pci_disable_pcie_error_reporting disables the device to send error
messages to root port when an error is detected.
::
int pci_aer_clear_nonfatal_status(struct pci_dev *dev);`
pci_aer_clear_nonfatal_status clears non-fatal errors in the uncorrectable
error status register.
Frequent Asked Questions
------------------------
@ -257,24 +223,6 @@ A:
Fatal error recovery will fail if the errors are reported by the
upstream ports who are attached by the service driver.
Q:
How does this infrastructure deal with driver that is not PCI
Express aware?
A:
This infrastructure calls the error callback functions of the
driver when an error happens. But if the driver is not aware of
PCI Express, the device might not report its own errors to root
port.
Q:
What modifications will that driver need to make it compatible
with the PCI Express AER Root driver?
A:
It could call the helper functions to enable AER in devices and
cleanup uncorrectable status register. Pls. refer to section 3.3.
Software error injection
========================