memc
—
MVME162-MVME177 Memory Controller Chip
The memc
devices are used on MVME162, MVME167, MVME172
and MVME177 boards to manage one or more DRAM modules.
Depending on the type of DRAM module fitted, the device will
either be a MEMC040 device or an MCECC device. The former manages a Parity
DRAM module while the latter manages an ECC DRAM module.
- memc0 at mainbus0.
- This is the normal autoconfiguration message indicating that the Memory
Controller Chip has been found and attached to the main processor
bus.
- memc0: Correctable error on CPU read access to 0x12345678.
- This indicates that an MCECC memory controller detected and corrected a
single bit error in one of the DRAM banks. There are a few variations on
the message where "CPU" can be replaced with "Peripheral
Device" or "Scrubber", and "read" can be
substituted for "write". This message is followed by some more
details which can help pin-point the error...
- memc0: ECC Syndrome 0x23 (DRAM Bank C, Bit#16).
- Pin-points exactly where the error occurred.
- memc0: Uncorrectable error on CPU read access to 0x12345678.
- Errors like this have the potential to corrupt data. As such, it is likely
the system will panic very soon afterwards.
The memc
driver does not yet fully support the MEMC040
(Parity) version of the device.