Linux* Base Drivers for Intel® Network Connection

Overview

Identifying Your Adapter

Building and Installation

Command Line Parameters

Speed and Duplex Configuration

Additional Configurations

Known Issues

Overview

NOTE: This release includes two Linux* Base Drivers for Intel® Network Connection. These drivers are named e1000 and igb. The igb driver must be installed to support any 82575-based network connections. All other network connections require the e1000 driver.

This file describes the Linux Base Drivers for Intel® Network Connection. These drivers supports the 2.4.x and 2.6.x kernels. These drivers includes support for Itanium® 2-based systems.

These drivers are only supported as a loadable module. Intel is not supplying patches against the kernel source to allow for static linking of the drivers. For questions related to hardware requirements, refer to the documentation supplied with your Intel Gigabit adapter. All hardware requirements listed apply to use with Linux.

This release includes support for Intel® I/O Acceleration Technology, Intel® I/OAT. You can find additional information on Intel I/OAT at http://www.intel.com/technology/ioacceleration/index.htm.

The following features are now available in supported kernels:

Channel Bonding documentation can be found in the Linux kernel source: /documentation/networking/bonding.txt

The driver information previously displayed in the /proc file system is not supported in this release. Alternatively, you can use ethtool (version 1.6 or later), lspci, and ifconfig to obtain the same information. Instructions on updating ethtool can be found in the section Additional Configurations later in this document.

NOTE: The Intel® 82562v 10/100 Network Connection only provides 10/100 support.

Identifying Your Adapter

For more information on how to identify your adapter, go to the Adapter & Driver ID Guide at:

http://support.intel.com/support/go/network/adapter/idguide.htm

For the latest Intel network drivers for Linux, refer to the following website. In the search field, enter your adapter name or type, or use the networking link on the left to search for your adapter:  

http://downloadcenter.intel.com/scripts-df-external/Support_Intel.aspx

Building and Installation

To build a binary RPM* package of this driver, run 'rpmbuild -tb <filename.tar.gz>'. Replace <filename.tar.gz> with the specific file name of the driver.

NOTES:

  • For the build to work properly, the currently running kernel MUST match the version and configuration of the installed kernel sources. If you have just recompiled the kernel reboot the system now.

  • RPM functionality has only been tested in Red Hat distributions.

  1. Move the base driver tar file to the directory of your choice. For example, use '/home/username/e1000' or '/usr/local/src/e1000'.

  2. Untar/unzip the archive, where <x.x.x> is the version number for the driver tar file:

    tar zxf e1000-<x.x.x>.tar.gz

  3. Change to the driver src directory, where <x.x.x> is the version number for the driver tar:

    cd e1000-<x.x.x>/src/

  4. Compile the driver module:

    make install

    The binary will be installed as:

    /lib/modules/<KERNEL VERSION>/kernel/drivers/net/e1000/e1000.[k]o

    The install location listed above is the default location. This may differ for various Linux distributions. For more information, go to ldistrib.htm.

  5. Load the module using either the insmod or modprobe command:

    modprobe e1000

    insmod e1000

    Note that for 2.6 kernels the insmod command can be used if the full path to the driver module is specified. For example:

        insmod /lib/modules/<KERNEL VERSION>/kernel/drivers/net/e1000/e1000.ko

    With 2.6 based kernels also make sure that older e1000 drivers are removed from the kernel, before loading the new module:

    rmmod e1000; modprobe e1000

  6. Assign an IP address to the interface by entering the following, where <x> is the interface number:

    ifconfig eth<x> <IP_address>

  7. Verify that the interface works. Enter the following, where <IP_address> is the IP address for another machine on the same subnet as the interface that is being tested:

    ping <IP_address>

To build igb driver with DCA:

This example assumes the ioatdma and igb sources are in /usr/src

  1. # unpack the ioatdma source, build and install

    cd /usr/src
    tar zxf ioatdma-<ioat version>.tar.gz
    cd ioatdma-<ioat version>
    make
    make install

  2. # unpack with igb driver, build with DCA support and install

    cd /usr/src
    tar zxf igb-<igb version>.tar.gz
    cd igb-<igb-version>/src
    make CFLAGS_EXTRA="-DIGB_DCA -I/usr/src/ioatdma-<ioat version>/include"
    make install

Command Line Parameters

If the driver is built as a module, the following optional parameters are used by entering them on the command line with the modprobe command using this syntax:

modprobe e1000 [<option>=<VAL1>,<VAL2>,...]

For example, with two Gigabit PCI adapters, entering:

modprobe e1000 TxDescriptors=80,128

loads the e1000 driver with 80 TX descriptors for the first adapter and 128 TX descriptors for the second adapter.

The default value for each parameter is generally the recommended setting, unless otherwise noted.

NOTES:

  • For more information about the AutoNeg, Duplex, and Speed parameters, see the Speed and Duplex Configuration section in this document.

  • For more information about the InterruptThrottleRate, RxIntDelay, TxIntDelay, RxAbsIntDelay, and TxAbsIntDelay parameters, see the application note at: http://www.intel.com/design/network/applnots/ap450.htm.

  • A descriptor describes a data buffer and attributes related to the data buffer. This information is accessed by the hardware.

Parameter Name Valid Range/Settings Default Description
AutoNeg

 (e1000 driver only)

 0x01-0x0F, 0x20-0x2F 0x2F This parameter is a bit mask that specifies which speed and duplex settings the board advertises. When this parameter is used, the Speed and Duplex parameters must not be specified.

This parameter is supported only on adapters using copper connections.

NOTE: Refer to the Speed and Duplex section of this readme for more information on the AutoNeg parameter.
Duplex

(e1000 driver only)

 0-2 (0=auto-negotiate, 1=half, 2=full) 0 Defines the direction in which data is allowed to flow. Can be either one or two-directional. If both Duplex and the link partner are set to auto-negotiate, the board auto-detects the correct duplex. If the link partner is forced (either full or half), Duplex defaults to half-duplex.

This parameter is supported only on adapters using copper connections.
FlowControl

(e1000 driver only)

 0-3 (0=none, 1=Rx only, 2=Tx only, 3=Rx&Tx) Read flow control settings from the EEPROM This parameter controls the automatic generation(Tx) and response(Rx) to Ethernet PAUSE frames.
InterruptThrottleRate (not supported on Intel(R) 82542, 82543 or 82544-based adapters)
Valid Range: 0,1,3,100-100000 (0=off, 1=dynamic, 3=dynamic conservative)
 		 3

The driver can limit the amount of interrupts per second that the adapter will generate for incoming packets. It does this by writing a value to the adapter that is based on the maximum amount of interrupts that the adapter will generate per second.

Setting InterruptThrottleRate to a value greater or equal to 100
will program the adapter to send out a maximum of that many interrupts per second, even if more packets have come in. This reduces interrupt load on the system and can lower CPU utilization under heavy load, but will increase latency as packets are not processed as quickly.

The default behaviour of the driver previously assumed a static InterruptThrottleRate value of 8000, providing a good fallback value for all traffic types, but lacking in small packet performance and latency. The hardware can handle many more small packets per second however, and for this reason an adaptive interrupt moderation algorithm was implemented.

Since 7.3.x, the driver has two adaptive modes (setting 1 or 3) in which it dynamically adjusts the InterruptThrottleRate value based on the traffic that it receives. After determining the type of incoming traffic in the last timeframe, it will adjust the InterruptThrottleRate to an appropriate value for that traffic.

The algorithm classifies the incoming traffic every interval into
classes. Once the class is determined, the InterruptThrottleRate value is adjusted to suit that traffic type the best. There are three classes defined: "Bulk traffic", for large amounts of packets of normal size; "Low latency", for small amounts of traffic and/or a significant percentage of small packets; and "Lowest latency", for almost completely small packets or minimal traffic.

In dynamic conservative mode, the InterruptThrottleRate value is set to 4000 for traffic that falls in class "Bulk traffic". If traffic falls in the "Low latency" or "Lowest latency" class, the InterruptThrottleRate is increased stepwise to 20000. This default mode is suitable for most applications.

For situations where low latency is vital such as cluster or grid computing, the algorithm can reduce latency even more when
InterruptThrottleRate is set to mode 1. In this mode, which operates
the same as mode 3, the InterruptThrottleRate will be increased stepwise to 70000 for traffic in class "Lowest latency".

Setting InterruptThrottleRate to 0 turns off any interrupt moderation
and may improve small packet latency, but is generally not suitable
for bulk throughput traffic

NOTE: InterruptThrottleRate takes precedence over the TxAbsIntDelay and RxAbsIntDelay parameters. In other words, minimizing the receive and/or transmit absolute delays does not force the controller to generate more interrupts than what the Interrupt Throttle Rate allows.

CAUTION: If you are using the Intel(R) PRO/1000 CT Network Connection (controller 82547), setting InterruptThrottleRate to a value greater than 75,000, may hang (stop transmitting) adapters
under certain network conditions. If this occurs a NETDEV
WATCHDOG message is logged in the system event log. In
addition, the controller is automatically reset, restoring the network connection. To eliminate the potential for the hang, ensure that InterruptThrottleRate is set no greater than 75,000 and is not set to 0.

NOTE: When e1000 is loaded with default settings and multiple adapters are in use simultaneously, the CPU utilization may increase non-linearly. In order to limit the CPU utilization without impacting
the overall throughput, we recommend that you load the driver as
follows:

modprobe e1000 InterruptThrottleRate=3000,3000,3000

This sets the InterruptThrottleRate to 3000 interrupts/sec for the first, second, and third instances of the driver. The range of 2000 to 3000 interrupts per second works on a majority of systems and is a good starting point, but the optimal value will be platform-specific. If CPU utilization is not a concern, use RX_POLLING (NAPI) and default driver settings.
RxDescriptors

(e1000 driver only)

80-4096

256
This value specifies the number of receive buffer descriptors allocated by the driver. Increasing this value allows the driver to buffer more incoming packets, at the expense of increased system memory utilization.

Each descriptor is 16 bytes. A receive buffer is also allocated for each descriptor and can be either 2048, 4096, 8192, or 16384 bytes, depending on the MTU setting. The maximum MTU size is 16110.

NOTE: MTU designates the frame size. It only needs to be set for Jumbo Frames. Depending on the available system resources, the request for a higher number of receive descriptors may be denied. In this case, use a lower number.
RxIntDelay

(e1000 driver only)

 0-65535 (0=off) 0 This value delays the generation of receive interrupts in units of 1.024 microseconds. Receive interrupt reduction can improve CPU efficiency if properly tuned for specific network traffic. Increasing this value adds extra latency to frame reception and can end up decreasing the throughput of TCP traffic. If the system is reporting dropped receives, this value may be set too high, causing the driver to run out of available receive descriptors.

CAUTION: When setting RxIntDelay to a value other than 0, adapters may hang (stop transmitting) under certain network conditions. If this occurs a NETDEV WATCHDOG message is logged in the system event log. In addition, the controller is automatically reset, restoring the network connection. To eliminate the potential for the hang ensure that RxIntDelay is set to zero.

RxAbsIntDelay

(e1000 driver only)

 0-65535 (0=off) 128 This value, in units of 1.024 microseconds, limits the delay in which a receive interrupt is generated. Useful only if RxIntDelay is non-zero, this value ensures that an interrupt is generated after the initial packet is received within the set amount of time. Proper tuning, along with RxIntDelay, may improve traffic throughput in specific network conditions.

This parameter is supported only on 82540, 82545 and later adapters.

Speed

(e1000 driver only)

 0, 10, 100, 1000 0 Speed forces the line speed to the specified value in megabits per second (Mbps). If this parameter is not specified or is set to 0 and the link partner is set to auto-negotiate, the board will auto-detect the correct speed. Duplex must also be set when Speed is set to either 10 or 100.

This parameter is supported only on adapters using copper connections.
TxDescriptors

(e1000 driver only)

80-4096

 256 This value is the number of transmit descriptors allocated by the driver. Increasing this value allows the driver to queue more transmits. Each descriptor is 16 bytes.
TxIntDelay

(e1000 driver only)

 0-65535 (0=off) 64 This value delays the generation of transmit interrupts in units of 1.024 microseconds. Transmit interrupt reduction can improve CPU efficiency if properly tuned for specific network traffic. If the system is reporting dropped transmits, this value may be set too high causing the driver to run out of available transmit descriptors.
TxAbsIntDelay

(e1000 driver only)

 0-65535 (0=off) 64

This value, in units of 1.024 microseconds, limits the delay in which a transmit interrupt is generated. Useful only if TxIntDelay is non-zero, this value ensures that an interrupt is generated after the initial packet is sent on the wire within the set amount of time. Proper tuning, along with TxIntDelay, may improve traffic throughput in specific network conditions.

This parameter is supported only on 82540, 82545 and later adapters.
XsumRX

(e1000 driver only)

 0-1 1 A value of '1' indicates that the driver should enable IP checksum offload for received packets (both UDP and TCP) to the adapter hardware.

This parameter is not supported on the 82542-based adapter.
Copybreak

(e1000 driver only)

 0-xxxxxxx (0=off) 256 Usage: insmod e1000.ko copybreak=128

Driver copies all packets below or equaling this size to a fresh rx buffer before handing it up the stack.

This parameter is different than other parameters, in that it is a single (not 1,1,1 etc.) parameter applied to all driver instances and it is also available during runtime at /sys/module/e1000/parameters/copybreak
SmartPowerDownEnable

(e1000 driver only)
 		 0-1
 		 1 (uses EEPROM settings); 0 (disabled for 82571EB and
82572-based network connections) 		Allows Phy to turn off in lower power states. The user can turn off
this parameter in supported chipsets.
KumeranLockLoss

(e1000 driver only)

 0-1 1 (enabled) This workaround skips resetting the Phy at shutdown for the initial
silicon releases of ICH8 systems.
LLIPort

(igb driver only)

 

 0-65535
 		 0 (disabled) LLI is configured with the LLIPort command-line parameter, which specifies which TCP should general Low Latency Interrupts.

For example, using LLIPort=80 would cause the board to generate an immediate interrupt upon receipt of any packet sent to TCP port 80 on the local machine.

CAUTION: Enabling LLI can result in an excessive number of interrupts/second that may cause problems with the system and in some cases may cause a kernel panic.

LLIPush

(igb driver only)

 0-1
 		 0 (disabled)
 		 LLIPush can be set to be enabled or disabled (default). It is most effective in an environment with many small transactions.
NOTE: Enabling LLIPush may allow a denial of service attack.
LLISize
(igb driver only)		 0-1500 0 (disabled) LLISize causes an immediate interrupt if the board receives a packet smaller than the specified size.
 

Speed and Duplex Configuration

Three keywords are used to control the speed and duplex configuration. These keywords are Speed, Duplex, and AutoNeg.

If the board uses a fiber interface, these keywords are ignored, and the fiber interface board only links at 1000 Mbps full-duplex.

For copper-based boards, the keywords interact as follows:

The default operation is auto-negotiate. The board advertises all supported speed and duplex combinations, and it links at the highest common speed and duplex mode IF the link partner is set to auto-negotiate.

If Speed = 1000, limited auto-negotiation is enabled and only 1000 Mbps is advertised (The 1000BaseT spec requires auto-negotiation.)

If Speed = 10 or 100, then both Speed and Duplex should  be set. Auto-negotiation is disabled, and the AutoNeg parameter is ignored. Partner SHOULD also be forced.

The AutoNeg parameter is used when more control is required over the auto-negotiation process. It should be used when you wish to control which speed and duplex combinations are advertised during the auto-negotiation process. The parameter may be specified as either a decimal or hexadecimal value as determined by the bitmap below.

Bit Position 7 6 5 4 3 2 1 0
Decimal Value 128 64 32 16 8 4 2 1
Hex Value 80 40 20 10 8  4 2 1
Speed (Mbps): N/A N/A 1000 N/A 100 100 10 10
Duplex:     Full   Full Half Full Half

Some examples of using AutoNeg:

     modprobe e1000 AutoNeg=0x01 (Restricts autonegotiation to 10 Half)
     modprobe e1000 AutoNeg=1 (Same as above)
     modprobe e1000 AutoNeg=0x02 (Restricts autonegotiation to 10 Full)
     modprobe e1000 AutoNeg=0x03 (Restricts autonegotiation to 10 Half or 10 Full)
     modprobe e1000 AutoNeg=0x04 (Restricts autonegotiation to 100 Half)
     modprobe e1000 AutoNeg=0x05 (Restricts autonegotiation to 10 Half or 100 Half)
     modprobe e1000 AutoNeg=0x020 (Restricts autonegotiation to 1000 Full)
     modprobe e1000 AutoNeg=32 (Same as above)

Note that when this parameter is used, Speed and Duplex must not be specified.

If the link partner is forced to a specific speed and duplex, then this parameter should not be used. Instead, use the Speed and Duplex parameters previously mentioned to force the adapter to the same speed and duplex.

Additional Configurations

Configuring the Driver on Different Distributions

Configuring a network driver to load properly when the system is started is distribution dependent. Typically, the configuration process involves adding an alias line to /etc/modules.conf or /etc/modprobe.conf as well as editing other system startup scripts and/or configuration files. Many popular Linux distributions ship with tools to make these changes for you. To learn the proper way to configure a network device for your system, refer to your distribution documentation. If during this process you are asked for the driver or module name, the name for the Linux Base Driver for the Gigabit family of adapters is e1000.

As an example, if you install the e1000 driver for two Gigabit adapters (eth0 and eth1) and set the speed and duplex to 10full and 100half, add the following to modules.conf or /etc/modprobe.conf:

alias eth0 e1000
alias eth1 e1000
options e1000 Speed=10,100 Duplex=2,1

Viewing Link Messages

Link messages will not be displayed to the console if the distribution is restricting system messages. In order to see network driver link messages on your console, set dmesg to eight by entering the following:

dmesg -n 8
NOTE: This setting is not saved across reboots.

Jumbo Frames

Jumbo Frames support is enabled by changing the Maximum Transmission Unit (MTU) to a value larger than the default value of 1500. Use the ifconfig command to increase the MTU size. For example:

ifconfig eth<x> mtu 9000 up

This setting is not saved across reboots. The setting change can be made permanent by adding MTU=9000 to the file: /etc/sysconfig/network-scripts/ifcfg-eth<x> (Red Hat distributions). Other distributions may store this setting in a different location.

NOTES:

  • To enable Jumbo Frames, increase the MTU size on the interface beyond 1500.

  • The maximum MTU setting for Jumbo Frames is 16110. This value coincides with the maximum Jumbo Frames size of 16128.

  • Some Intel gigabit adapters that support Jumbo Frames have a frame size limit of 9238 bytes, with a corresponding MTU size limit of 9216 bytes. The adapters with this limitation are based on the Intel® 82571EB, 82572EI, 82573L, 82566, 82562, 82575, and 80003ES2LAN controllers. These correspond to the following product names:
    Intel® PRO/1000 PT Server Adapter
    Intel® PRO/1000 PT Desktop Adapter
    Intel® PRO/1000 PT Network Connection
    Intel® PRO/1000 PT Dual Port Server Adapter
    Intel® PRO/1000 PT Dual Port Network Connection
    Intel® PRO/1000 PF Server Adapter
    Intel® PRO/1000 PF Network Connection
    Intel® PRO/1000 PF Dual Port Server Adapter
    Intel® PRO/1000 PB Server Connection
    Intel® PRO/1000 PL Network Connection
    Intel® PRO/1000 EB Network Connection with I/O Acceleration
    Intel® PRO/1000 EB Backplane Connection with I/O Acceleration
    Intel® PRO/1000 PT Quad Port Server Adapter
    Intel® PRO/1000 PF Quad Port Server Adapter
    Intel® 82566DM-2 Gigabit Network Connection
    Intel® Gigabit VT Quad Port Server Adapter
    Intel® Gigabit PT Quad Port Server ExpressModule

  • Using Jumbo Frames at 10 or 100 Mbps may result in poor performance or loss of link.

  • Adapters based on the Intel® 82542 and 82573V/E controller do not support Jumbo Frames. These correspond to the following product names:
    Intel® PRO/1000 Gigabit Server Adapter
    Intel® PRO/1000 PM Network Connection

  • The following adapters do not support Jumbo Frames:
    Intel® 82562V 10/100 Network Connection
    Intel® 82566DM Gigabit Network Connection
    Intel® 82566DC Gigabit Network Connection
    Intel® 82566MM Gigabit Network Connection
    Intel® 82566MC Gigabit Network Connection
    Intel® 82562GT 10/100 Network Connection
    Intel® 82562G 10/100 Network Connection
    Intel® 82566DC-2 Gigabit Network Connection
    Intel® 82562V-2 10/100 Network Connection
    Intel® 82562G-2 10/100 Network Connection
    Intel® 82562GT-2 10/100 Network Connection

Ethtool

The driver utilizes the ethtool interface for driver configuration and diagnostics, as well as displaying statistical information. Ethtool version 3.0 or later is required for this functionality, although we strongly recommend downloading the latest version at:

http://sourceforge.net/projects/gkernel.

Enabling Wake on LAN* (WoL)

WoL is configured through the Ethtool* utility. Ethtool is included with all versions of Red Hat after Red Hat 7.2. For other Linux distributions, download and install Ethtool from the following website: http://sourceforge.net/projects/gkernel.

For instructions on enabling WoL with Ethtool, refer to the website listed above.

WoL will be enabled on the system during the next shut down or reboot. For this driver version, in order to enable WoL, the e1000 driver must be loaded prior to shutting down or suspending the system.

NOTES: Wake On LAN is only supported on port A for the following devices:
  • Intel® PRO/1000 PT Dual Port Network Connection
  • Intel® PRO/1000 PT Dual Port Server Connection
  • Intel® PRO/1000 PT Dual Port Server Adapter
  • Intel® PRO/1000 PF Dual Port Server Adapter
  • Intel® PRO/1000 PT Quad Port Server Adapter
  • Intel® Gigabit PT Quad Port Server ExpressModule

Wake On LAN is not supported for the Intel® Gigabit VT Quad Port Server Adapter.

NAPI

NAPI (Rx polling mode) is supported in the e1000 driver. NAPI is enabled or disabled based on the configuration of the kernel. To override the default, use the following compile-time flags.

To enable NAPI, compile the driver module, passing in a configuration option:

make CFLAGS_EXTRA=-DE1000_NAPI install

To disable NAPI, compile the driver module, passing in a configuration option:

make CFLAGS_EXTRA=-DE1000_NO_NAPI install

See http://www.cyberus.ca/~hadi/usenix-paper.tgz for more information on NAPI.

Multiqueue (82575-based network connections)

In this mode, a separate MSI-X vector is allocated for each queue and one for "other" interrupts such as link status change and errors. All interrupts are throttled via interrupt moderation. Interrupt moderation must be used to avoid interrupt storms while the driver is processing one interrupt. The moderation value should be at least as large as the expected time for the driver to process an interrupt. Multiqueue is off by default.

MSI-X support is required for Multiqueue. If MSI-X is not found, the system will fallback to MSI or to Legacy interrupts.

NOTES: Do not use MSI-X with the 2.6.19 or 2.6.20 kernels. We recommend the 2.6.21 or later kernel.

On some kernels a reboot is required to switch between a single queue mode and multiqueue modes, or vice-versa.

Multiqueue can be enabled with a compile flag:
          # make CFLAGS_EXTRA=-DCONFIG_IGB_MQ_RX

This will give you up to four rx queues without AIM (but using a simple adaptive algorithm for dynamic interrupt moderation). We have found that this provides
acceptable throughput but uses a lot more CPU than single-queue mode due to more interrupts. This mode might be useful if you are handling multiple connections
using a lot of small packets and you aren't concerned about CPU utilization. Note that tx cleanups are handled during rx processing.

With this option you can get up to five MSI-X vectors - one per RX queue and one for link. You will never get more queues than CPUs, so if you have a dual-proc
server you'll only get two RX queues.

To enable a separate vector for TX, use:
# make CFLAGS_EXTRA=-DCONFIG_IGB_SEPARATE_TX_HANDLER

This will allocate a separate handler for tx cleanups. This might be useful if you have a lot of CPU cores under heavy load and want to spread the processing load around.

With this option, you would get three MSI-X vectors: one for TX, one for RX, and one for link.

The previous two options can be combined:
# make CFLAGS_EXTRA="-DCONFIG_IGB_RX_MQ -DCONFIG_IGB_SEPARATE_TX_HANDLER" (quotes are required).

This will disable AIM, and give you up to six MSI-X vectors: one for each RX queue (up to four), one for TX cleanups, and one for link.

Currently there is no kernel support for multiple TX queues.

Known Issues

NOTE: For distribution-specific information, see ldistrib.htm.

Using the igb driver on 2.4 or older 2.6 based kernels

Due to limited support for PCI-Express in 2.4 kernels and older 2.6 kernels, the igb driver may run into interrupt related problems on some systems, such as no link or hang when bringing up the device.

We recommend the newer 2.6 based kernels, as these kernels correctly configure the PCI-Express configuration space of the adapter and all intervening bridges. If you are required to use a 2.4 kernel, use a 2.4 kernel newer than 2.4.30. For 2.6 kernels we recommend using the 2.6.21 kernel or newer.

Alternatively, on 2.6 kernels you may disable MSI support in the kernel by booting with the "pci=nomsi" option or permanently disable MSI support in your kernel by configuring your kernel with CONFIG_PCI_MSI unset.

Intel® Active Management Technology 2.0, 2.1, 2.5 not supported in conjunction with Linux driver

Detected Tx Unit Hang in Quad Port Adapters

In some cases ports 3 and 4 don't pass traffic and report 'Detected Tx Unit Hang' followed by 'NETDEV WATCHDOG: ethX: transmit timed out' errors. Ports 1 and 2 don't show any errors and will pass traffic.

This issue MAY be resolved by updating to the latest kernel and BIOS. The user is encouraged to run an OS that fully supports MSI interrupts. You can check your system's BIOS by downloading the Linux Firmware Developer Kit that can be obtained at http://www.linuxfirmwarekit.org/

82573(V/L/E) TX Unit Hang Messages

Several adapters with the 82573 chipset display "TX unit hang" messages during normal operation with the e1000 driver. The issue appears both with TSO enabled and disabled, and is caused by a power management function that is enabled in the EEPROM. Early releases of the chipsets to vendors had the EEPROM bit that enabled the feature. After the issue was discovered newer adapters were released with the feature disabled in the EEPROM.

If you encounter the problem in an adapter, and the chipset is an 82573-based one, you can verify that your adapter needs the fix by using ethtool: 

 # ethtool -e eth0
 Offset          Values
 ------          ------
 0x0000          00 12 34 56 fe dc 30 0d 46 f7 f4 00 ff ff ff ff
 0x0010          ff ff ff ff 6b 02 8c 10 d9 15 8c 10 86 80 de 83
                                                           ^^

The value at offset 0x001e (de) has bit 0 unset. This enables the problematic power saving feature. In this case, the EEPROM needs to read "df" at offset 0x001e.

A one-time EEPROM fix is available as a shell script. This script will verify that the adapter is applicable to the fix and if the fix is needed or not. If the fix is required, it applies the change to the EEPROM and updates the checksum. The user must reboot the system after applying the fix if changes were made to the EEPROM.

Example output of the script: 

 # bash fixeep-82573-dspd.sh eth0
 eth0: is a "82573E Gigabit Ethernet Controller"
 This fixup is applicable to your hardware
 executing command: ethtool -E eth0 magic 0x109a8086 offset 0x1e value 0xdf
 Change made. You *MUST* reboot your machine before changes take effect!

The script can be downloaded at http://e1000.sourceforge.net/files/fixeep-82573-dspd.sh

Dropped Receive Packets on Half-duplex 10/100 Networks

If you have an Intel PCI Express adapter running at 10mbps or 100mbps, half-duplex, you may observe occasional dropped receive packets. There are no workarounds for this problem in this network configuration. The network must be updated to operate in full-duplex, and/or 1000mbps only.

Compiling the Driver

When trying to compile the driver by running make install, the following error may occur:  "Linux kernel source not configured - missing version.h"

To solve this issue, create the version.h file by going to the Linux source tree and entering:

make include/linux/version.h

Jumbo Frames System Requirement

Memory allocation failures have been observed on Linux systems with 64 MB of RAM or less that are running Jumbo Frames. If you are using Jumbo Frames, your system may require more than the advertised minimum requirement of 64 MB of system memory.

Performance Degradation with Jumbo Frames

Degradation in throughput performance may be observed in some Jumbo frames environments. If this is observed, increasing the application's socket buffer size and/or increasing the /proc/sys/net/ipv4/tcp_*mem entry values may help. See the specific application manual and /usr/src/linux*/Documentation/networking/ip-sysctl.txt for more details.

Jumbo frames on Foundry BigIron 8000 switch

There is a known issue using Jumbo frames when connected to a Foundry BigIron 8000 switch. This is a 3rd party limitation. If you experience loss of packets, lower the MTU size.

Allocating Rx Buffers when Using Jumbo Frames

Allocating Rx buffers when using Jumbo Frames on 2.6.x kernels may fail if the available memory is heavily fragmented. This issue may be seen with PCI-X
adapters or with packet split disabled. This can be reduced or eliminated by changing the amount of available memory for receive buffer allocation, by increasing /proc/sys/vm/min_free_kbytes.

Multiple Interfaces on Same Ethernet Broadcast Network

Due to the default ARP behavior on Linux, it is not possible to have one system on two IP networks in the same Ethernet broadcast domain (non-partitioned switch) behave as expected. All Ethernet interfaces will respond to IP traffic for any IP address assigned to the system. This results in unbalanced receive traffic.

If you have multiple interfaces in a server, either turn on ARP filtering by entering:

        echo 1 > /proc/sys/net/ipv4/conf/all/arp_filter

(this only works if your kernel's version is higher than 2.4.5)

NOTE: This setting is not saved across reboots. The configuration change can be made permanent by adding the line:

net.ipv4.conf.all.arp_filter = 1

to the file /etc/sysctl.conf

   or,

install the interfaces in separate broadcast domains (either in different switches or in a switch partitioned to VLANs).

82541/82547 can't link or is slow to link with some link partners

There is a known compatibility issue with 82541/82547 and some low-end switches where the link will not be established, or will be slow to establish. In particular, these switches are known to be incompatible with 82541/82547:

     Planex FXG-08TE
     I-O Data ETG-SH8

To workaround this issue, the driver can be compiled with an override of the PHY's master/slave setting. Forcing master or forcing slave mode will improve time-to-link.

     # make CFLAGS_EXTRA=-DE1000_MASTER_SLAVE=<n>

Where <n> is:

        0 = Hardware default
        1 = Master mode
        2 = Slave mode
        3 = Auto master/slave

Disable rx flow control with ethtool

In order to disable receive flow control using ethtool, you must turn off auto-negotiation on the same command line.

For example:

     ethtool -A eth? autoneg off rx off

Unplugging network cable while ethtool -p is running

In kernel versions 2.5.50 and later (including 2.6 kernel), unplugging the network cable while ethtool -p is running will cause the system to
become unresponsive to keyboard commands, except for control-alt-delete. Restarting the system appears to be the only remedy.

Last modified on 8/20/07 10:51a Revision 28