Patch "EDAC, sb_edac: Don't create a second memory controller if HA1 is not present" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

EDAC, sb_edac: Don't create a second memory controller if HA1 is not present

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
edac-sb_edac-don-t-create-a-second-memory-controller-if-ha1-is-not-present.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Qiuxu Zhuo <[email protected]>
Date: Wed, 13 Sep 2017 18:42:14 +0800
Subject: EDAC, sb_edac: Don't create a second memory controller if HA1 is not present

From: Qiuxu Zhuo <[email protected]>

commit 15cc3ae001873845b5d842e212478a6570c7d938 upstream.

Yi Zhang reported the following failure on a 2-socket Haswell (E5-2603v3) server (DELL PowerEdge 730xd):

EDAC sbridge: Some needed devices are missing
EDAC MC: Removed device 0 for sb_edac.c Haswell SrcID#0_Ha#0: DEV 0000:7f:12.0 EDAC MC: Removed device 1 for sb_edac.c Haswell SrcID#1_Ha#0: DEV 0000:ff:12.0 EDAC sbridge: Couldn't find mci handler
EDAC sbridge: Couldn't find mci handler
EDAC sbridge: Failed to register device with error -19.

The refactored sb_edac driver creates the IMC1 (the 2nd memory controller) if any IMC1 device is present. In this case only HA1_TA of IMC1 was present, but the driver expected to find HA1/HA1_TM/HA1_TAD[0-3] devices too, leading to the above failure.

The document [1] says the 'E5-2603 v3' CPU has 4 memory channels max. Yi Zhang inserted one DIMM per channel for each CPU, and did random error address injection test with this patch:

      4024  addresses fell in TOLM hole area
     12715  addresses fell in CPU_SrcID#0_Ha#0_Chan#0_DIMM#0
     12774  addresses fell in CPU_SrcID#0_Ha#0_Chan#1_DIMM#0
     12798  addresses fell in CPU_SrcID#0_Ha#0_Chan#2_DIMM#0
     12913  addresses fell in CPU_SrcID#0_Ha#0_Chan#3_DIMM#0
     12674  addresses fell in CPU_SrcID#1_Ha#0_Chan#0_DIMM#0
     12686  addresses fell in CPU_SrcID#1_Ha#0_Chan#1_DIMM#0
     12882  addresses fell in CPU_SrcID#1_Ha#0_Chan#2_DIMM#0
     12934  addresses fell in CPU_SrcID#1_Ha#0_Chan#3_DIMM#0
    106400  addresses were injected totally.

The test result shows that all the 4 channels belong to IMC0 per CPU, so the server really only has one IMC per CPU.

In the 1st page of chapter 2 in datasheet [2], it also says 'E5-2600 v3' implements either one or two IMCs. For CPUs with one IMC, IMC1 is not used and should be ignored.

Thus, do not create a second memory controller if the key HA1 is absent.

[1] http://ark.intel.com/products/83349/Intel-Xeon-Processor-E5-2603-v3-15M-Cache-1_60-GHz
[2] https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/xeon-e5-v3-datasheet-vol-2.pdf

---
 drivers/edac/sb_edac.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

@@ -462,6 +462,7 @@ static const struct pci_id_table pci_dev
 static const struct pci_id_descr pci_dev_descr_ibridge[] = {
 		/* Processor Home Agent */
 	{ PCI_DESCR(PCI_DEVICE_ID_INTEL_IBRIDGE_IMC_HA0,        0, IMC0) },
+	{ PCI_DESCR(PCI_DEVICE_ID_INTEL_IBRIDGE_IMC_HA1,        1, IMC1) },
 
 		/* Memory controller */
 	{ PCI_DESCR(PCI_DEVICE_ID_INTEL_IBRIDGE_IMC_HA0_TA,     0, IMC0) },

@@ -472,7 +473,6 @@ static const struct pci_id_descr pci_dev
 	{ PCI_DESCR(PCI_DEVICE_ID_INTEL_IBRIDGE_IMC_HA0_TAD3,   0, IMC0) },
 
 		/* Optional, mode 2HA */
-	{ PCI_DESCR(PCI_DEVICE_ID_INTEL_IBRIDGE_IMC_HA1,        1, IMC1) },
 	{ PCI_DESCR(PCI_DEVICE_ID_INTEL_IBRIDGE_IMC_HA1_TA,     1, IMC1) },
 	{ PCI_DESCR(PCI_DEVICE_ID_INTEL_IBRIDGE_IMC_HA1_RAS,    1, IMC1) },
 	{ PCI_DESCR(PCI_DEVICE_ID_INTEL_IBRIDGE_IMC_HA1_TAD0,   1, IMC1) },

@@ -2291,6 +2291,13 @@ static int sbridge_get_onedevice(struct
 next_imc:
 	sbridge_dev = get_sbridge_dev(bus, dev_descr->dom, multi_bus, sbridge_dev);
 	if (!sbridge_dev) {
+		/* If the HA1 wasn't found, don't create EDAC second memory controller */
+		if (dev_descr->dom == IMC1 && devno != 1) {
+			edac_dbg(0, "Skip IMC1: %04x:%04x (since HA1 was absent)\n",
+				 PCI_VENDOR_ID_INTEL, dev_descr->dev_id);
+			pci_dev_put(pdev);
+			return 0;
+		}
 
 		if (dev_descr->dom == SOCK)
 			goto out_imc;

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/edac-sb_edac-don-t-create-a-second-memory-controller-if-ha1-is-not-present.patch