diff options
| author | Bjorn Helgaas <bhelgaas@google.com> | 2016-09-06 16:24:37 -0500 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2016-09-14 15:27:49 -0500 |
| commit | 7ece14175376051b18a9b97f0e6125cb8b864155 (patch) | |
| tree | bcfcc5f761bf26b4356634c67e74bd9ae2e44163 /Documentation/PCI/pcieaer-howto.txt | |
| parent | 9ff25e6b3eb0012297288dfa87930c7b62ef6ab1 (diff) | |
PCI/AER: Remove aerdriver.forceload kernel parameter
Per the PCI Firmware spec, r3.0, sec 4.5.1, on ACPI systems, the OS must
not use AER unless _OSC is present and _OSC grants AER control to the OS.
The aerdriver.forceload kernel parameter was a way to enable Linux AER
support on ACPI systems that lack _OSC or fail to grant control the the OS.
Enabling Linux AER support when the firmware doesn't want us to is a recipe
for problems, e.g., the firmware might be handling AER itself.
Remove the aerdriver.forceload kernel parameter and related supporting
code.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'Documentation/PCI/pcieaer-howto.txt')
| -rw-r--r-- | Documentation/PCI/pcieaer-howto.txt | 22 |
1 files changed, 9 insertions, 13 deletions
diff --git a/Documentation/PCI/pcieaer-howto.txt b/Documentation/PCI/pcieaer-howto.txt index 4956df36c59d..ea8cafba255c 100644 --- a/Documentation/PCI/pcieaer-howto.txt +++ b/Documentation/PCI/pcieaer-howto.txt @@ -49,21 +49,17 @@ depends on CONFIG_PCIEPORTBUS, so pls. set CONFIG_PCIEPORTBUS=y and CONFIG_PCIEAER = y. 2.2 Load PCI Express AER Root Driver -There is a case where a system has AER support in BIOS. Enabling the AER -Root driver and having AER support in BIOS may result unpredictable -behavior. To avoid this conflict, a successful load of the AER Root driver -requires ACPI _OSC support in the BIOS to allow the AER Root driver to -request for native control of AER. See the PCI FW 3.0 Specification for -details regarding OSC usage. Currently, lots of firmwares don't provide -_OSC support while they use PCI Express. To support such firmwares, -forceload, a parameter of type bool, could enable AER to continue to -be initiated although firmwares have no _OSC support. To enable the -walkaround, pls. add aerdriver.forceload=y to kernel boot parameter line -when booting kernel. Note that forceload=n by default. + +Some systems have AER support in firmware. Enabling Linux AER support at +the same time the firmware handles AER may result in unpredictable +behavior. Therefore, Linux does not handle AER events unless the firmware +grants AER control to the OS via the ACPI _OSC method. See the PCI FW 3.0 +Specification for details regarding _OSC usage. 2.3 AER error output -When a PCI-E AER error is captured, an error message will be outputted to -console. If it's a correctable error, it is outputted as a warning. + +When a PCIe AER error is captured, an error message will be output to +console. If it's a correctable error, it is output as a warning. Otherwise, it is printed as an error. So users could choose different log level to filter out correctable error messages. |