EM(4) Kernel Interfaces Manual EM(4) NAME em -- Intel(R) PRO/1000 Gigabit Ethernet adapter driver SYNOPSIS To compile this driver into the kernel, place the following line in your kernel configuration file: device em Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5): if_em_load="YES" DESCRIPTION The em driver provides support for PCI Gigabit Ethernet adapters based on the Intel 82540, 82541ER, 82541PI, 82542, 82543, 82544, 82545, 82546, 82546EB, 82546GB, 82547, 82571, 81572 and 82573 Ethernet con- troller chips. The driver supports Transmit/Receive checksum offload and Jumbo Frames only on 82540, 82543, 82544 and 82546-based adapters. For further hardware information, see the README included with the dri- ver. For questions related to hardware requirements, refer to the documenta- tion supplied with your Intel PRO/1000 adapter. All hardware require- ments listed apply to use with FreeBSD. Support for Jumbo Frames is provided via the interface MTU setting. Selecting an MTU larger than 1500 bytes with the ifconfig(8) utility configures the adapter to receive and transmit Jumbo Frames. The maxi- mum MTU size for Jumbo Frames is 16114. This driver version supports VLANs. For information on enabling VLANs, see the README. The em driver supports the following media types: autoselect Enables auto-negotiation for speed and duplex. 10baseT/UTP Sets 10Mbps operation. Use the mediaopt option to select full-duplex mode. 100baseTX Sets 100Mbps operation. Use the mediaopt option to select full-duplex mode. 1000baseSX Sets 1000Mbps operation. Only full-duplex mode is sup- ported at this speed. 1000baseTX Sets 1000Mbps operation. Only full-duplex mode is sup- ported at this speed. The em driver supports the following media options: full-duplex Forces full-duplex operation half-duplex Forces half-duplex operation. Only use mediaopt to set the driver to full-duplex. If mediaopt is not specified, the driver defaults to half-duplex. For more information on configuring this device, see ifconfig(8). HARDWARE The em driver supports Gigabit Ethernet adapters based on the Intel 82540, 82541ER, 82541PI, 82542, 82543, 82544, 82545, 82546, 82546EB, 82546GB, 82547, 82571, 82572 and 82573 controller chips: • Intel PRO/1000 CT Network Connection (82547) • Intel PRO/1000 F Server Adapter (82543) • Intel PRO/1000 Gigabit Server Adapter (82542) • Intel PRO/1000 GT Desktop Adapter (82541PI) • Intel PRO/1000 MF Dual Port Server Adapter (82546) • Intel PRO/1000 MF Server Adapter (82545) • Intel PRO/1000 MF Server Adapter (LX) (82545) • Intel PRO/1000 MT Desktop Adapter (82540) • Intel PRO/1000 MT Desktop Adapter (82541) • Intel PRO/1000 MT Dual Port Server Adapter (82546) • Intel PRO/1000 MT Quad Port Server Adapter (82546EB) • Intel PRO/1000 MT Server Adapter (82545) • Intel PRO/1000 T Desktop Adapter (82544) • Intel PRO/1000 T Server Adapter (82543) • Intel PRO/1000 XF Server Adapter (82544) • Intel PRO/1000 XT Server Adapter (82544) LOADER TUNABLES Tunables can be set at the loader(8) prompt before booting the kernel or stored in loader.conf(5). hw.em.rxd Number of receive descriptors allocated by the driver. The de- fault value is 256. The 82542 and 82543-based adapters can handle up to 256 descriptors, while others can have up to 4096. hw.em.txd Number of transmit descriptors allocated by the driver. The default value is 256. The 82542 and 82543-based adapters can handle up to 256 descriptors, while others can have up to 4096. hw.em.rx_int_delay This value delays the generation of receive interrupts in units of 1.024 microseconds. The default value is 0, since adapters may hang with this feature being enabled. hw.em.rx_abs_int_delayIfhw.em.rx_int_delay is non-zero, this tunable limits the max- imum delay in which a receive interrupt is generated. hw.em.tx_int_delay This value delays the generation of transmit interrupts in units of 1.024 microseconds. The default value is 64. hw.em.tx_abs_int_delayIfhw.em.tx_int_delay is non-zero, this tunable limits the max- imum delay in which a transmit interrupt is generated. DIAGNOSTICS em%d: Unable to allocate bus resource: memory A fatal initialization error has occurred. em%d: Unable to allocate bus resource: interrupt A fatal initializa- tion error has occurred. em%d: watchdog timeout -- resetting The device has stopped responding to the network, or there is a problem with the network connection (ca- ble). SUPPORT For additional information regarding building and installation, see the README included with the driver. For general information and support, go to the Intel support website at: http://support.intel.com. If an issue is identified with the released source code on the sup- ported kernel with a supported adapter, email the specific information related to the issue to <freebsdnic@mailbox.intel.com>. SEE ALSO arp(4), netintro(4), ng_ether(4), polling(4), vlan(4), ifconfig(8) HISTORY The em device driver first appeared in FreeBSD 4.4. AUTHORS The em driver was written by Intel Corporation <freebsdnic@mailbox.intel.com>. BUGS Hardware-assisted VLAN processing is disabled by default. You can en- able it on an em interface using ifconfig(8). FreeBSD 6.1 November 27, 2005 EM(4)