What: /sys/firmware/opal/elog
Date: Feb 2014
Contact: Stewart Smith <[email protected]>
Description:
This directory exposes error log entries retrieved
through the OPAL firmware interface.
Each error log is identified by a unique ID and will
exist until explicitly acknowledged to firmware.
Each log entry has a directory in /sys/firmware/opal/elog.
Log entries may be purged by the service processor
before retrieved by firmware or retrieved/acknowledged by
Linux if there is no room for more log entries.
In the event that Linux has retrieved the log entries
but not explicitly acknowledged them to firmware and
the service processor needs more room for log entries,
the only remaining copy of a log message may be in
Linux.
Typically, a user space daemon will monitor for new
entries, read them out and acknowledge them.
The service processor may be able to store more log
entries than firmware can, so after you acknowledge
an event from Linux you may instantly get another one
from the queue that was generated some time in the past.
The raw log format is a binary format. We currently
do not parse this at all in kernel, leaving it up to
user space to solve the problem. In future, we may
do more parsing in kernel and add more files to make
it easier for simple user space processes to extract
more information.
For each log entry (directory), there are the following
files:
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id: An ASCII representation of the ID of the
error log, in hex - e.g. "0x01".
type: An ASCII representation of the type id and
description of the type of error log.
Currently just "0x00 PEL" - platform error log.
In the future there may be additional types.
raw: A read-only binary file that can be read
to get the raw log entry. These are
<16kb, often just hundreds of bytes and
"average" 2kb.
acknowledge: Writing 'ack' to this file will acknowledge
the error log to firmware (and in turn
the service processor, if applicable).
Shortly after acknowledging it, the log
entry will be removed from sysfs.
Reading this file will list the supported
operations (currently just acknowledge).
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