EM(4)

📦 version 12.2, in debian bookworm, debian trixie, ubuntu jammy, ubuntu noble, ubuntu questing, ubuntu resolute, ubuntu stonking

✨ EM(4) ✨ — the Intel(R) PRO/1000 Gigabit Ethernet adapter driver 💖

okay bestie, buckle UP because this is the manual page for em, and she's an icon, she's a legend, and she is the moment 👑

🌸 NAME 🌸

em — the Intel(R) PRO/1000 Gigabit Ethernet adapter driver, aka the girl who makes your network go brrr 🦋

🎀 SYNOPSIS 🎀

so like, if you wanna compile this driver into the kernel (main character energy, no modules), you drop these lines into your kernel configuration file:

device iflib
device em

orrr, alternatively, if you'd rather load the driver as a module at boot time (lowkey easier, ngl), you put this line in loader.conf(5):

if_em_load="YES"

💅 DESCRIPTION 💅

okay so 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, 82573, and 82574 Ethernet controller chips. that's a whole lot of numbers bestie, and every single one of them matters 💜

she also provides support for PCI Express Gigabit Ethernet adapters based on the Intel 82575, 82576, 82580, i21x and i35x. PCIe girlies rise 🙈

the driver supports Transmit/Receive checksum offload and Jumbo Frames on all but 82542-based adapters. yes, ALL of them except that one. she's special like that.

furthermore (love that word), she supports TCP segmentation offload (TSO) on all adapters but those based on the 82543, 82544 and 82547 controller chips. the identification LEDs of the adapters supported by the em driver can be controlled via the led(4) API for localization purposes — yes bestie, you can make your NIC blink so you can find it in the server rack 🎀✨. For further hardware information, see the README included with the driver.

For questions related to hardware requirements, refer to the documentation supplied with your Intel PRO/1000 adapter. All hardware requirements listed apply to use with FreeBSD. no cap.

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 maximum MTU size for Jumbo Frames is 16114. huge. massive. iconic.

This driver supports hardware assisted VLANs. The em driver supports the following media types:

  • autoselect — Enables auto-negotiation for speed and duplex. she's flexible, she's adaptable, she's everything 💖
  • 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 supported at this speed.
  • 1000baseTX — Sets 1000Mbps operation. Only full-duplex mode is supported 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. ⚠️ don't come crying to me if you forget this one bestie

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, 82573, 82574, 82575, 82576, and 82580 controller chips:

  • Intel Gigabit ET Dual Port Server Adapter (82576)
  • Intel Gigabit VT Quad Port Server Adapter (82575)
  • Intel Single, Dual and Quad Gigabit Ethernet Controller (82580)
  • Intel i210 and i211 Gigabit Ethernet Controller
  • Intel i350 and i354 Gigabit Ethernet Controller
  • 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 PF Dual Port Server Adapter (82571)
  • Intel PRO/1000 PF Quad Port Server Adapter (82571)
  • Intel PRO/1000 PF Server Adapter (82572)
  • Intel PRO/1000 PT Desktop Adapter (82572)
  • Intel PRO/1000 PT Dual Port Server Adapter (82571)
  • Intel PRO/1000 PT Quad Port Server Adapter (82571)
  • Intel PRO/1000 PT Server Adapter (82572)
  • 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)

look at that list. she ate and left no crumbs 💅

🌈 LOADER TUNABLES 🌈

Tunables can be set at the loader(8) prompt before booting the kernel or stored in loader.conf(5). so many knobs to turn, so little time 🫶

  • hw.em.disable_crc_stripping — Disable or enable hardware stripping of CRC field. This is mostly useful on BMC/IPMI shared interfaces where stripping the CRC causes remote access over IPMI to fail. Default 0 (enabled).
  • hw.em.eee_setting — Disable or enable Energy Efficient Ethernet. Default 1 (disabled). (yes bestie, 1 means disabled here, read it twice, i'll wait 😭)
  • hw.em.msix — Enable or disable MSI-X style interrupts. Default 1 (enabled).
  • hw.em.smart_pwr_down — Enable or disable smart power down features on newer adapters. Default 0 (disabled).
  • hw.em.sbp — Show bad packets when in promiscuous mode. Default 0 (off).
  • hw.em.rxd — Number of receive descriptors allocated by the driver. The default value is 1024 for adapters newer than 82547, and 256 for older ones. 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 1024 for adapters newer than 82547, and 256 for older ones. 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. 💀 noted, we leave that one alone
  • hw.em.rx_abs_int_delay — If hw.em.rx_int_delay is non-zero, this tunable limits the maximum 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_delay — If hw.em.tx_int_delay is non-zero, this tunable limits the maximum delay in which a transmit interrupt is generated.

🦋 FILES 🦋

  • /dev/led/em* — identification LED device nodes 💡

⭐ EXAMPLES ⭐

Make the identification LED of em0 blink:

echo f2 > /dev/led/em0

Turn the identification LED of em0 off again:

echo 0 > /dev/led/em0

she's blinking. she's thriving. she's found in the rack 🎀

😭 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 initialization 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 (cable). bestie check the cable. i'm serious. check the cable first 😭

💜 SUPPORT 💜

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 supported kernel with a supported adapter, email the specific information related to the issue to ⟨freebsd@intel.com⟩.

🧚 SEE ALSO 🧚

altq(4), arp(4), iflib(4), led(4), netintro(4), ng_ether(4), polling(4), vlan(4), ifconfig(8)

iykyk 📚

👑 HISTORY 👑

The em device driver first appeared in FreeBSD 4.4. em was merged with the igb device driver and converted to the iflib framework in FreeBSD 12.0.

glow-up arc, honestly ✨

🫶 AUTHORS 🫶

The em driver was originally written by Intel Corporation <freebsd@intel.com>. It was merged with igb driver and converted to the iflib framework by Matthew Macy <mmacy@mattmacy.io> and Sean Bruno <sbruno@FreeBSD.org>.

and that's the whole page bestie, you're officially an em expert, no cap 💖✨🎀🦋🌸💅🫶

this was the EM(4) Kernel Interfaces Manual, from the Debian crew, dated January 30, 2019 — thanks for reading, mwah 💋

📦 where this page comes from