| What: /sys/devices/.../sun |
| Contact: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> |
| The file contains a Slot-unique ID which provided by the _SUN |
| method in the ACPI namespace. The value is written in Advanced |
| Configuration and Power Interface Specification as follows: |
| "The _SUN value is required to be unique among the slots of |
| the same type. It is also recommended that this number match |
| the slot number printed on the physical slot whenever possible." |
| So reading the sysfs file, we can identify a physical position |
| of the slot in the system. |