diff options
| author | Bjorn Helgaas <bhelgaas@google.com> | 2016-09-06 17:24:37 -0400 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2016-09-14 16:27:49 -0400 |
| commit | 7ece14175376051b18a9b97f0e6125cb8b864155 (patch) | |
| tree | bcfcc5f761bf26b4356634c67e74bd9ae2e44163 /Documentation/PCI | |
| 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')
| -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 | |||
| 49 | CONFIG_PCIEAER = y. | 49 | CONFIG_PCIEAER = y. |
| 50 | 50 | ||
| 51 | 2.2 Load PCI Express AER Root Driver | 51 | 2.2 Load PCI Express AER Root Driver |
| 52 | There is a case where a system has AER support in BIOS. Enabling the AER | 52 | |
| 53 | Root driver and having AER support in BIOS may result unpredictable | 53 | Some systems have AER support in firmware. Enabling Linux AER support at |
| 54 | behavior. To avoid this conflict, a successful load of the AER Root driver | 54 | the same time the firmware handles AER may result in unpredictable |
| 55 | requires ACPI _OSC support in the BIOS to allow the AER Root driver to | 55 | behavior. Therefore, Linux does not handle AER events unless the firmware |
| 56 | request for native control of AER. See the PCI FW 3.0 Specification for | 56 | grants AER control to the OS via the ACPI _OSC method. See the PCI FW 3.0 |
| 57 | details regarding OSC usage. Currently, lots of firmwares don't provide | 57 | Specification for details regarding _OSC usage. |
| 58 | _OSC support while they use PCI Express. To support such firmwares, | ||
| 59 | forceload, a parameter of type bool, could enable AER to continue to | ||
| 60 | be initiated although firmwares have no _OSC support. To enable the | ||
| 61 | walkaround, pls. add aerdriver.forceload=y to kernel boot parameter line | ||
| 62 | when booting kernel. Note that forceload=n by default. | ||
| 63 | 58 | ||
| 64 | 2.3 AER error output | 59 | 2.3 AER error output |
| 65 | When a PCI-E AER error is captured, an error message will be outputted to | 60 | |
| 66 | console. If it's a correctable error, it is outputted as a warning. | 61 | When a PCIe AER error is captured, an error message will be output to |
| 62 | console. If it's a correctable error, it is output as a warning. | ||
| 67 | Otherwise, it is printed as an error. So users could choose different | 63 | Otherwise, it is printed as an error. So users could choose different |
| 68 | log level to filter out correctable error messages. | 64 | log level to filter out correctable error messages. |
| 69 | 65 | ||
