Documentation/ABI/stable/sysfs-firmware-opal-elog

   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
  60                                 operations (curently just acknowledge).