1 What: /sys/firmware/opal/elog
3 Contact: Stewart Smith <stewart@linux.vnet.ibm.com>
5 This directory exposes error log entries retrieved
6 through the OPAL firmware interface.
8 Each error log is identified by a unique ID and will
9 exist until explicitly acknowledged to firmware.
11 Each log entry has a directory in /sys/firmware/opal/elog.
13 Log entries may be purged by the service processor
14 before retrieved by firmware or retrieved/acknowledged by
15 Linux if there is no room for more log entries.
17 In the event that Linux has retrieved the log entries
18 but not explicitly acknowledged them to firmware and
19 the service processor needs more room for log entries,
20 the only remaining copy of a log message may be in
23 Typically, a user space daemon will monitor for new
24 entries, read them out and acknowledge them.
26 The service processor may be able to store more log
27 entries than firmware can, so after you acknowledge
28 an event from Linux you may instantly get another one
29 from the queue that was generated some time in the past.
31 The raw log format is a binary format. We currently
32 do not parse this at all in kernel, leaving it up to
33 user space to solve the problem. In future, we may
34 do more parsing in kernel and add more files to make
35 it easier for simple user space processes to extract
38 For each log entry (directory), there are the following
41 ============== ================================================
42 id: An ASCII representation of the ID of the
43 error log, in hex - e.g. "0x01".
45 type: An ASCII representation of the type id and
46 description of the type of error log.
47 Currently just "0x00 PEL" - platform error log.
48 In the future there may be additional types.
50 raw: A read-only binary file that can be read
51 to get the raw log entry. These are
52 <16kb, often just hundreds of bytes and
55 acknowledge: Writing 'ack' to this file will acknowledge
56 the error log to firmware (and in turn
57 the service processor, if applicable).
58 Shortly after acknowledging it, the log
59 entry will be removed from sysfs.
60 Reading this file will list the supported
61 operations (currently just acknowledge).
62 ============== ================================================