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774fea1a SS |
1 | What: /sys/firmware/opal/elog |
2 | Date: Feb 2014 | |
3 | Contact: Stewart Smith <stewart@linux.vnet.ibm.com> | |
4 | Description: | |
5 | This directory exposes error log entries retrieved | |
6 | through the OPAL firmware interface. | |
7 | ||
8 | Each error log is identified by a unique ID and will | |
9 | exist until explicitly acknowledged to firmware. | |
10 | ||
11 | Each log entry has a directory in /sys/firmware/opal/elog. | |
12 | ||
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. | |
16 | ||
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 | |
21 | Linux. | |
22 | ||
23 | Typically, a user space daemon will monitor for new | |
24 | entries, read them out and acknowledge them. | |
25 | ||
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. | |
30 | ||
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 | |
36 | more information. | |
37 | ||
38 | For each log entry (directory), there are the following | |
39 | files: | |
40 | ||
41 | id: An ASCII representation of the ID of the | |
42 | error log, in hex - e.g. "0x01". | |
43 | ||
44 | type: An ASCII representation of the type id and | |
45 | description of the type of error log. | |
46 | Currently just "0x00 PEL" - platform error log. | |
47 | In the future there may be additional types. | |
48 | ||
49 | raw: A read-only binary file that can be read | |
50 | to get the raw log entry. These are | |
51 | <16kb, often just hundreds of bytes and | |
52 | "average" 2kb. | |
53 | ||
54 | acknowledge: Writing 'ack' to this file will acknowledge | |
55 | the error log to firmware (and in turn | |
56 | the service processor, if applicable). | |
57 | Shortly after acknowledging it, the log | |
58 | entry will be removed from sysfs. | |
59 | Reading this file will list the supported | |
83432ef3 | 60 | operations (currently just acknowledge). |