Sun Microsystems Sun Ultra 450, Manual

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CPU Deconfiguration
If any CPU is marked as having failed POST, or if a user chooses to disable a CPU,
then the OBP will set the Master Disable bit of the affected CPU, which essentially
turns it off as an active UPA device until the next power-on system reset.
Memory Deconfiguration
Detecting and isolating system memory problems is one of the more difficult
diagnostic tasks. This problem is further complicated by the system’s various modes
of memory interleaving as well as the possibility of mismatching memory DIMMs
within the same bank.
Given a failed memory component, the firmware will deconfigure the entire bank
associated with the failure. This policy also means that the degraded configuration
may mean a lower interleave factor, a less than 100 percent utilization of remaining
banks, or both depending on the interleave factor.
ASR User Override Capability
While the default settings will properly configure or deconfigure an Ultra 450 system
in most cases, it is useful to provide advanced users with a manual override
capability. Because of the nature of “soft” versus “hard” deconfiguration, it is
necessary to provide two related but different override mechanisms.
“Soft” Deconfigure Override
For any subsystem represented by a distinct device tree node, users may disable that
function via the NVRAM variable
asr-disable-list
, which is simply a list of
device tree paths separated by spaces.
ok setenv asr-disable-list /pci/ebus/ecpp /pci@1f,4000/scsi@3
The Ultra 450 OBP will use this information to created disabled status properties for
each node listed in the variable
asr-disable-list
.
“Hard” Deconfigure Override
For overriding those subsystems that require “hard” deconfiguration (CPU and
memory), the OBP commands
asr-enable
and
asr-disable
are used to
selectively enable or disable each subsystem.
System Configuration Parameters
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