Processor Configuration Registers
176
Datasheet, Volume 2
2.10.41 SLOTCTL—Slot Control Register
PCI Express Slot related registers allow for the support of Hot Plug.
B/D/F/Type:
0/6/0/PCI
Address Offset:
B8–B9h
Reset Value:
0000h
Access:
RO,
Size:
16 bits
BIOS Optimal Default
0h
Bit
Attr
Reset
Value
RST/
PWR
Description
15:13
RO
0h
Reserved
12
RO
0b
Uncore
Reserved for Data Link Layer State Changed Enable
(DLLSCE)
If the Data Link Layer Link Active capability is implemented, when
set to 1b, this field enables software notification when Data Link
Layer Link Active field is changed.
If the Data Link Layer Link Active capability is not implemented,
this bit is permitted to be read-only with a value of 0b.
11
RO
0b
Uncore
Reserved for Electromechanical Interlock Control (EIC)
If an Electromechanical Interlock is implemented, a write of 1b to
this field causes the state of the interlock to toggle. A write of 0b to
this field has no effect. A read to this register always returns a 0.
10
RO
0b
Uncore
Reserved for Power Controller Control (PCC)
If a Power Controller is implemented, this field when written sets
the power state of the slot per the defined encodings. Reads of this
field must reflect the value from the latest write, even if the
corresponding hotplug command is not complete, unless software
issues a write without waiting for the previous command to
complete in which case the read value is undefined.
Depending on the form factor, the power is turned on/off either to
the slot or within the adapter. Note that in some cases the power
controller may autonomously remove slot power or not respond to
a power-up request based on a detected fault condition,
independent of the Power Controller Control setting.
0 = Power On
1 = Power Off
If the Power Controller Implemented field in the Slot Capabilities
register is set to 0b, writes to this field have no effect and the read
value of this field is undefined.
9:8
RO
00b
Uncore
Reserved Power Indicator Control (PIC)
If a Power Indicator is implemented, writes to this field set the
Power Indicator to the written state. Reads of this field must reflect
the value from the latest write, even if the corresponding hot-plug
command is not complete, unless software issues a write without
waiting for the previous command to complete in which case the
read value is undefined.
00 = Reserved
01 = On
10 = Blink
11 = Off
If the Power Indicator Present bit in the Slot Capabilities register is
0b, this field is permitted to be read only with a value of 00b.