[PATCH 3A/3 good] e820: Add the unknown-12 Memory type (DDR3-NvDIMM)
From: Boaz Harrosh
Date: Mon Feb 23 2015 - 07:46:36 EST
There are multiple vendors of DDR3 NvDIMMs out in the market today.
At various stages of development/production. It is estimated that
there are already more the 100ds of thousands chips sold to
testers and sites.
All the BIOS vendors I know of, tagged these chips at e820 table
as type-12 memory.
Now the ACPI comity, as far as I know, did not yet define a
standard type for NvDIMM. Also, as far as I know any NvDIMM
standard will only be defined for DDR4. So DDR3 NvDIMM is
probably stuck with this none STD type.
I Wish and call the ACPI comity to Define that NvDIMM is type-12.
Also for DDR4
In this patch I name type-12 "unknown-12". This is because of
ACPI politics that refuse to reserve type-12 as DDR3-NvDIMM
and members keep saying:
"What if ACPI assigns type-12 for something else in future"
[And I say: Then just don't. Please?]
Signed-off-by: Boaz Harrosh <boaz@xxxxxxxxxxxxx>
arch/x86/kernel/e820.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 18a9850..023dd29 100644
@@ -25,6 +25,11 @@
+/* These are nonstandard Memory types that we do not want in the exported
+ * header.
+#define E820_UNKNOWN_12 12 /* This is the unofficial DDR3-NVDIMM */
* The e820 map is the map that gets modified e.g. with command line parameters
* and that is also registered with modifications in the kernel resource tree
@@ -169,6 +174,9 @@ static void __init e820_print_type(u32 type)
+ case E820_UNKNOWN_12:
+ printk(KERN_CONT "unknown-12");
printk(KERN_CONT "type %u", type);
@@ -928,6 +936,7 @@ static inline const char *e820_type_to_string(int e820_type)
case E820_NVS: return "ACPI Non-volatile Storage";
case E820_UNUSABLE: return "Unusable memory";
case E820_RESERVED: return "reserved";
+ case E820_UNKNOWN_12: return "unkown-12";
default: return "reserved-unkown";
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/