edac.txt

linux 内核源代码

	This attribute file displays the total count of correctable
	errors that have occurred on this memory controller. This
	count is very important to examine. CEs provide early
	indications that a DIMM is beginning to fail. This count
	field should be monitored for non-zero values and report
	such information to the system administrator.


Total Correctable Errors count attribute file:

	'ce_noinfo_count'

	This attribute file displays the number of CEs that
	have occurred wherewith no informations as to which DIMM slot
	is having errors. Memory is handicapped, but operational,
	yet no information is available to indicate which slot
	the failing memory is in. This count field should be also
	be monitored for non-zero values.

Device Symlink:

	'device'

	Symlink to the memory controller device.

Sdram memory scrubbing rate:

	'sdram_scrub_rate'

	Read/Write attribute file that controls memory scrubbing. The scrubbing
	rate is set by writing a minimum bandwith in bytes/sec to the attribute
	file. The rate will be translated to an internal value that gives at
	least the specified rate.

	Reading the file will return the actual scrubbing rate employed.

	If configuration fails or memory scrubbing is not implemented, the value
	of the attribute file will be -1.



============================================================================
'csrowX' DIRECTORIES

In the 'csrowX' directories are EDAC control and attribute files for
this 'X" instance of csrow:


Total Uncorrectable Errors count attribute file:

	'ue_count'

	This attribute file displays the total count of uncorrectable
	errors that have occurred on this csrow. If panic_on_ue is set
	this counter will not have a chance to increment, since EDAC
	will panic the system.


Total Correctable Errors count attribute file:

	'ce_count'

	This attribute file displays the total count of correctable
	errors that have occurred on this csrow. This
	count is very important to examine. CEs provide early
	indications that a DIMM is beginning to fail. This count
	field should be monitored for non-zero values and report
	such information to the system administrator.


Total memory managed by this csrow attribute file:

	'size_mb'

	This attribute file displays, in count of megabytes, of memory
	that this csrow contains.


Memory Type attribute file:

	'mem_type'

	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


EDAC Mode of operation attribute file:

	'edac_mode'

	This attribute file will display what type of Error detection
	and correction is being utilized.


Device type attribute file:

	'dev_type'

	This attribute file will display what type of DRAM device is
	being utilized on this DIMM.
	Examples:
		x1
		x2
		x4
		x8


Channel 0 CE Count attribute file:

	'ch0_ce_count'

	This attribute file will display the count of CEs on this
	DIMM located in channel 0.


Channel 0 UE Count attribute file:

	'ch0_ue_count'

	This attribute file will display the count of UEs on this
	DIMM located in channel 0.


Channel 0 DIMM Label control file:

	'ch0_dimm_label'

	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.


Channel 1 CE Count attribute file:

	'ch1_ce_count'

	This attribute file will display the count of CEs on this
	DIMM located in channel 1.


Channel 1 UE Count attribute file:

	'ch1_ue_count'

	This attribute file will display the count of UEs on this
	DIMM located in channel 0.


Channel 1 DIMM Label control file:

	'ch1_dimm_label'

	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.


============================================================================
SYSTEM LOGGING

If logging for UEs and CEs are enabled then system logs will have
error notices indicating errors that have been detected:

EDAC MC0: CE page 0x283, offset 0xce0, grain 8, syndrome 0x6ec3, row 0,
channel 1 "DIMM_B1": amd76x_edac

EDAC MC0: CE page 0x1e5, offset 0xfb0, grain 8, syndrome 0xb741, row 0,
channel 1 "DIMM_B1": amd76x_edac


The structure of the message is:
	the memory controller			(MC0)
	Error type				(CE)
	memory page				(0x283)
	offset in the page			(0xce0)
	the byte granularity 			(grain 8)
		or resolution of the error
	the error syndrome			(0xb741)
	memory row				(row 0)
	memory channel				(channel 1)
	DIMM label, if set prior		(DIMM B1
	and then an optional, driver-specific message that may
		have additional information.

Both UEs and CEs with no info will lack all but memory controller,
error type, a notice of "no info" and then an optional,
driver-specific error message.



============================================================================
PCI Bus Parity Detection


On Header Type 00 devices the primary status is looked at
for any parity error regardless of whether Parity is enabled on the
device.  (The spec indicates parity is generated in some cases).
On Header Type 01 bridges, the secondary status register is also
looked at to see if parity occurred on the bus on the other side of
the bridge.


SYSFS CONFIGURATION

Under /sys/devices/system/edac/pci are control and attribute files as follows:


Enable/Disable PCI Parity checking control file:

	'check_pci_parity'


	This control file enables or disables the PCI Bus Parity scanning
	operation. Writing a 1 to this file enables the scanning. Writing
	a 0 to this file disables the scanning.

	Enable:
	echo "1" >/sys/devices/system/edac/pci/check_pci_parity

	Disable:
	echo "0" >/sys/devices/system/edac/pci/check_pci_parity



Panic on PCI PARITY Error:

	'panic_on_pci_parity'


	This control files enables or disables panicking when a parity
	error has been detected.


	module/kernel parameter: panic_on_pci_parity=[0|1]

	Enable:
	echo "1" >/sys/devices/system/edac/pci/panic_on_pci_parity

	Disable:
	echo "0" >/sys/devices/system/edac/pci/panic_on_pci_parity


Parity Count:

	'pci_parity_count'

	This attribute file will display the number of parity errors that
	have been detected.



=======================================================================


EDAC_DEVICE type of device

In the header file, edac_core.h, there is a series of edac_device structures
and APIs for the EDAC_DEVICE.

User space access to an edac_device is through the sysfs interface.

At the location /sys/devices/system/edac (sysfs) new edac_device devices will
appear.

There is a three level tree beneath the above 'edac' directory. For example,
the 'test_device_edac' device (found at the bluesmoke.sourceforget.net website)
installs itself as:

	/sys/devices/systm/edac/test-instance

in this directory are various controls, a symlink and one or more 'instance'
directorys.

The standard default controls are:

	log_ce		boolean to log CE events
	log_ue		boolean to log UE events
	panic_on_ue	boolean to 'panic' the system if an UE is encountered
			(default off, can be set true via startup script)
	poll_msec	time period between POLL cycles for events

The test_device_edac device adds at least one of its own custom control:

	test_bits	which in the current test driver does nothing but
			show how it is installed. A ported driver can
			add one or more such controls and/or attributes
			for specific uses.
			One out-of-tree driver uses controls here to allow
			for ERROR INJECTION operations to hardware
			injection registers

The symlink points to the 'struct dev' that is registered for this edac_device.

INSTANCES

One or more instance directories are present. For the 'test_device_edac' case:

	test-instance0


In this directory there are two default counter attributes, which are totals of
counter in deeper subdirectories.

	ce_count	total of CE events of subdirectories
	ue_count	total of UE events of subdirectories

BLOCKS

At the lowest directory level is the 'block' directory. There can be 0, 1
or more blocks specified in each instance.

	test-block0


In this directory the default attributes are:

	ce_count	which is counter of CE events for this 'block'
			of hardware being monitored
	ue_count	which is counter of UE events for this 'block'
			of hardware being monitored


The 'test_device_edac' device adds 4 attributes and 1 control:

	test-block-bits-0	for every POLL cycle this counter
				is incremented
	test-block-bits-1	every 10 cycles, this counter is bumped once,
				and test-block-bits-0 is set to 0
	test-block-bits-2	every 100 cycles, this counter is bumped once,
				and test-block-bits-1 is set to 0
	test-block-bits-3	every 1000 cycles, this counter is bumped once,
				and test-block-bits-2 is set to 0


	reset-counters		writing ANY thing to this control will
				reset all the above counters.


Use of the 'test_device_edac' driver should any others to create their own
unique drivers for their hardware systems.

The 'test_device_edac' sample driver is located at the
bluesmoke.sourceforge.net project site for EDAC.