Sun Microsystems Netra CT 410, Service Manual

Page: 283 / 296

Appendix C Error Messages C-11
C.4 I
2
C Complaints
Message
NO ADDERSS ACK 80
Cause
This message indicates a problem with Inter-Integrated Circuit (I
2
C), and often it’s
the
pcf8584
driver that complains, followed by the address it is trying to access (for
example,
NO ADDRESS ACK 80
. indicates a problem with address 80, which is the
fixed address of the system controller board).
Most of the Sun drivers print a secondary error message, but the principal error
message comes from
pcf8584
. The interface to this is through an ioctl, so it is done
through software. This message indicates a problem, but not the severity. Sometimes
such a message is normal.
For example when a power supply is removed, the Present line goes low and the
SCB sets the bit high (interrupt). The kernel
pcf8584
goes down the device line
querying for interrupts in the order in which the devices boot, each one answering.
The message
8584 NO ADDR ACK 0x9E
occurs when the device is removed. Because
it happened after the driver tried to query the hardware, this spurious error message
occurs. This condition happens with fans and power supplies.
Action
If the error message occurs during a hot-swap operation, it is erroneous and can be
ignored. If the error message occurs during normal operation, it might indicate a
problem with the I
2
C device.