Intel

®

82599 10 GbE Controller—Device Disable

4.4.4.2 Multi-Function Advertisement

If one of the LAN devices is disabled and function 0 is the only active function, the 82599 is no longer a multi-function device. The 82599 normally reports a 0x80 in the PCI configuration header, indicating multi-function capability. However, if a LAN is disabled and only function 0 is active, the 82599 reports a 0x0 in this field to signify singlefunction capability.

4.4.4.3 Interrupt Utilization

When both LAN devices are enabled, the 82599 uses the PCI legacy interrupts of both ports for interrupt reporting. The EEPROM configuration controls the

Interrupt Pin

field of the PCI configuration header to be advertised for each LAN device to comply with PCI specification requirements.

However, if either LAN device is disabled, then the legacy PCI interrupt of port A must be used for the remaining LAN device, therefore the EEPROM configuration must be set accordingly. Under these circumstances, the

Interrupt Pin

field of the PCI configuration header always reports a value of 0x1, indicating INTA# pin usage, which means legacy

PCI interrupt of port A is used.

4.4.4.4 Power Reporting

When both LAN devices are enabled, the PCI Power Management register block has the capability of reporting a common power value. The common power value is reflected in the

Data

field of the PCI Power Management registers. The value reported as common power is specified via an EEPROM field, and is reflected in the

Data

field each time the

Data_Select

field has a value of 0x8 (0x8 = common power value select).

When only one LAN port is enabled and the 82599 appears as a single-function device, the common power value, if selected, reports 0x0 (undefined value), as common power is undefined for a single-function device.

4.5 Device Disable

4.5.1 Overview

When both LAN ports are disabled following a Power on Reset / LAN Power Good/ PCIe

Reset/ In-Band Reset, the LANx_DIS_N signals should be tied statically to low. In this state the device is disabled, LAN ports are powered down, all internal clocks are shut, and the PCIe connection is powered down (similar to L2 state).

166 331520-004