[19/19] EDAC, Documentation: Describe CPER module definition and DIMM ranks

Message ID 20191010202418.25098-20-rrichter@marvell.com
State Superseded
Headers show
Series
  • EDAC: Rework edac_mc and ghes drivers
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Commit Message

Robert Richter Oct. 10, 2019, 8:25 p.m.
Update on CPER DIMM naming convention and DIMM ranks.

Signed-off-by: Robert Richter <rrichter@marvell.com>

---
 Documentation/admin-guide/ras.rst | 31 +++++++++++++++++++------------
 1 file changed, 19 insertions(+), 12 deletions(-)

-- 
2.20.1

Comments

Mauro Carvalho Chehab Oct. 11, 2019, 11:29 a.m. | #1
Em Thu, 10 Oct 2019 20:25:42 +0000
Robert Richter <rrichter@marvell.com> escreveu:

> Update on CPER DIMM naming convention and DIMM ranks.

> 

> Signed-off-by: Robert Richter <rrichter@marvell.com>


Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>


> ---

>  Documentation/admin-guide/ras.rst | 31 +++++++++++++++++++------------

>  1 file changed, 19 insertions(+), 12 deletions(-)

> 

> diff --git a/Documentation/admin-guide/ras.rst b/Documentation/admin-guide/ras.rst

> index 2b20f5f7380d..26e02a59f0f4 100644

> --- a/Documentation/admin-guide/ras.rst

> +++ b/Documentation/admin-guide/ras.rst

> @@ -330,9 +330,12 @@ There can be multiple csrows and multiple channels.

>  

>  .. [#f4] Nowadays, the term DIMM (Dual In-line Memory Module) is widely

>    used to refer to a memory module, although there are other memory

> -  packaging alternatives, like SO-DIMM, SIMM, etc. Along this document,

> -  and inside the EDAC system, the term "dimm" is used for all memory

> -  modules, even when they use a different kind of packaging.

> +  packaging alternatives, like SO-DIMM, SIMM, etc. The UEFI

> +  specification (Version 2.7) defines a memory module in the Common

> +  Platform Error Record (CPER) section to be an SMBIOS Memory Device

> +  (Type 17). Along this document, and inside the EDAC system, the term

> +  "dimm" is used for all memory modules, even when they use a

> +  different kind of packaging.

>  

>  Memory controllers allow for several csrows, with 8 csrows being a

>  typical value. Yet, the actual number of csrows depends on the layout of

> @@ -349,12 +352,14 @@ controllers. The following example will assume 2 channels:

>  	|            |  ``ch0``  |  ``ch1``  |

>  	+============+===========+===========+

>  	| ``csrow0`` |  DIMM_A0  |  DIMM_B0  |

> -	+------------+           |           |

> -	| ``csrow1`` |           |           |

> +	|            |   rank0   |   rank0   |

> +	+------------+     -     |     -     |

> +	| ``csrow1`` |   rank1   |   rank1   |

>  	+------------+-----------+-----------+

>  	| ``csrow2`` |  DIMM_A1  | DIMM_B1   |

> -	+------------+           |           |

> -	| ``csrow3`` |           |           |

> +	|            |   rank0   |   rank0   |

> +	+------------+     -     |     -     |

> +	| ``csrow3`` |   rank1   |   rank1   |

>  	+------------+-----------+-----------+

>  

>  In the above example, there are 4 physical slots on the motherboard

> @@ -374,11 +379,13 @@ which the memory DIMM is placed. Thus, when 1 DIMM is placed in each

>  Channel, the csrows cross both DIMMs.

>  

>  Memory DIMMs come single or dual "ranked". A rank is a populated csrow.

> -Thus, 2 single ranked DIMMs, placed in slots DIMM_A0 and DIMM_B0 above

> -will have just one csrow (csrow0). csrow1 will be empty. On the other

> -hand, when 2 dual ranked DIMMs are similarly placed, then both csrow0

> -and csrow1 will be populated. The pattern repeats itself for csrow2 and

> -csrow3.

> +In the example above 2 dual ranked DIMMs are similarly placed. Thus,

> +both csrow0 and csrow1 are populated. On the other hand, when 2 single

> +ranked DIMMs are placed in slots DIMM_A0 and DIMM_B0, then they will

> +have just one csrow (csrow0) and csrow1 will be empty. The pattern

> +repeats itself for csrow2 and csrow3. Also note that some memory

> +controller doesn't have any logic to identify the memory module, see

> +``rankX`` directories below.

>  

>  The representation of the above is reflected in the directory

>  tree in EDAC's sysfs interface. Starting in directory




Thanks,
Mauro

Patch

diff --git a/Documentation/admin-guide/ras.rst b/Documentation/admin-guide/ras.rst
index 2b20f5f7380d..26e02a59f0f4 100644
--- a/Documentation/admin-guide/ras.rst
+++ b/Documentation/admin-guide/ras.rst
@@ -330,9 +330,12 @@  There can be multiple csrows and multiple channels.
 
 .. [#f4] Nowadays, the term DIMM (Dual In-line Memory Module) is widely
   used to refer to a memory module, although there are other memory
-  packaging alternatives, like SO-DIMM, SIMM, etc. Along this document,
-  and inside the EDAC system, the term "dimm" is used for all memory
-  modules, even when they use a different kind of packaging.
+  packaging alternatives, like SO-DIMM, SIMM, etc. The UEFI
+  specification (Version 2.7) defines a memory module in the Common
+  Platform Error Record (CPER) section to be an SMBIOS Memory Device
+  (Type 17). Along this document, and inside the EDAC system, the term
+  "dimm" is used for all memory modules, even when they use a
+  different kind of packaging.
 
 Memory controllers allow for several csrows, with 8 csrows being a
 typical value. Yet, the actual number of csrows depends on the layout of
@@ -349,12 +352,14 @@  controllers. The following example will assume 2 channels:
 	|            |  ``ch0``  |  ``ch1``  |
 	+============+===========+===========+
 	| ``csrow0`` |  DIMM_A0  |  DIMM_B0  |
-	+------------+           |           |
-	| ``csrow1`` |           |           |
+	|            |   rank0   |   rank0   |
+	+------------+     -     |     -     |
+	| ``csrow1`` |   rank1   |   rank1   |
 	+------------+-----------+-----------+
 	| ``csrow2`` |  DIMM_A1  | DIMM_B1   |
-	+------------+           |           |
-	| ``csrow3`` |           |           |
+	|            |   rank0   |   rank0   |
+	+------------+     -     |     -     |
+	| ``csrow3`` |   rank1   |   rank1   |
 	+------------+-----------+-----------+
 
 In the above example, there are 4 physical slots on the motherboard
@@ -374,11 +379,13 @@  which the memory DIMM is placed. Thus, when 1 DIMM is placed in each
 Channel, the csrows cross both DIMMs.
 
 Memory DIMMs come single or dual "ranked". A rank is a populated csrow.
-Thus, 2 single ranked DIMMs, placed in slots DIMM_A0 and DIMM_B0 above
-will have just one csrow (csrow0). csrow1 will be empty. On the other
-hand, when 2 dual ranked DIMMs are similarly placed, then both csrow0
-and csrow1 will be populated. The pattern repeats itself for csrow2 and
-csrow3.
+In the example above 2 dual ranked DIMMs are similarly placed. Thus,
+both csrow0 and csrow1 are populated. On the other hand, when 2 single
+ranked DIMMs are placed in slots DIMM_A0 and DIMM_B0, then they will
+have just one csrow (csrow0) and csrow1 will be empty. The pattern
+repeats itself for csrow2 and csrow3. Also note that some memory
+controller doesn't have any logic to identify the memory module, see
+``rankX`` directories below.
 
 The representation of the above is reflected in the directory
 tree in EDAC's sysfs interface. Starting in directory