diff options
| -rw-r--r-- | Documentation/edac.txt | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/Documentation/edac.txt b/Documentation/edac.txt index f89cfd85ae13..502988524519 100644 --- a/Documentation/edac.txt +++ b/Documentation/edac.txt @@ -208,6 +208,126 @@ For a description of the sysfs API, please see: Documentation/ABI/testing/sysfs-devices-edac +``dimmX`` or ``rankX`` directories +---------------------------------- + +The recommended way to use the EDAC subsystem is to look at the information +provided by the ``dimmX`` or ``rankX`` directories [#f5]_. + +A typical EDAC system has the following structure under +``/sys/devices/system/edac/``\ [#f6]_:: + + /sys/devices/system/edac/ + ├── mc + │ ├── mc0 + │ │ ├── ce_count + │ │ ├── ce_noinfo_count + │ │ ├── dimm0 + │ │ │ ├── dimm_dev_type + │ │ │ ├── dimm_edac_mode + │ │ │ ├── dimm_label + │ │ │ ├── dimm_location + │ │ │ ├── dimm_mem_type + │ │ │ ├── size + │ │ │ └── uevent + │ │ ├── max_location + │ │ ├── mc_name + │ │ ├── reset_counters + │ │ ├── seconds_since_reset + │ │ ├── size_mb + │ │ ├── ue_count + │ │ ├── ue_noinfo_count + │ │ └── uevent + │ ├── mc1 + │ │ ├── ce_count + │ │ ├── ce_noinfo_count + │ │ ├── dimm0 + │ │ │ ├── dimm_dev_type + │ │ │ ├── dimm_edac_mode + │ │ │ ├── dimm_label + │ │ │ ├── dimm_location + │ │ │ ├── dimm_mem_type + │ │ │ ├── size + │ │ │ └── uevent + │ │ ├── max_location + │ │ ├── mc_name + │ │ ├── reset_counters + │ │ ├── seconds_since_reset + │ │ ├── size_mb + │ │ ├── ue_count + │ │ ├── ue_noinfo_count + │ │ └── uevent + │ └── uevent + └── uevent + +In the ``dimmX`` directories are EDAC control and attribute files for +this ``X`` memory module: + +- ``size`` - Total memory managed by this csrow attribute file + + This attribute file displays, in count of megabytes, the memory + that this csrow contains. + +- ``dimm_dev_type`` - Device type attribute file + + This attribute file will display what type of DRAM device is + being utilized on this DIMM. + Examples: + + - x1 + - x2 + - x4 + - x8 + +- ``dimm_edac_mode`` - EDAC Mode of operation attribute file + + This attribute file will display what type of Error detection + and correction is being utilized. + +- ``dimm_label`` - memory module label control file + + This control file allows this DIMM to have a label assigned + to it. With this label in the module, when errors occur + the output can provide the DIMM label in the system log. + This becomes vital for panic events to isolate the + cause of the UE event. + + DIMM Labels must be assigned after booting, with information + that correctly identifies the physical slot with its + silk screen label. This information is currently very + motherboard specific and determination of this information + must occur in userland at this time. + +- ``dimm_location`` - location of the memory module + + The location can have up to 3 levels, and describe how the + memory controller identifies the location of a memory module. + Depending on the type of memory and memory controller, it + can be: + + - *csrow* and *channel* - used when the memory controller + doesn't identify a single DIMM - e. g. in ``rankX`` dir; + - *branch*, *channel*, *slot* - typically used on FB-DIMM memory + controllers; + - *channel*, *slot* - used on Nehalem and newer Intel drivers. + +- ``dimm_mem_type`` - Memory Type attribute file + + This attribute file will display what type of memory is currently + on this csrow. Normally, either buffered or unbuffered memory. + Examples: + + - Registered-DDR + - Unbuffered-DDR + +.. [#f5] On some systems, the memory controller doesn't have any logic + to identify the memory module. On such systems, the directory is called ``rankX`` and works on a similar way as the ``csrowX`` directories. + On modern Intel memory controllers, the memory controller identifies the + memory modules directly. On such systems, the directory is called ``dimmX``. + +.. [#f6] There are also some ``power`` directories and ``subsystem`` + symlinks inside the sysfs mapping that are automatically created by + the sysfs subsystem. Currently, they serve no purpose. 'csrowX' directories -------------------- |