linux/Documentation/networking/e1000.txt
<<
>>
Prefs
   1Linux* Base Driver for the Intel(R) PRO/1000 Family of Adapters
   2===============================================================
   3
   4September 26, 2006
   5
   6
   7Contents
   8========
   9
  10- In This Release
  11- Identifying Your Adapter
  12- Building and Installation
  13- Command Line Parameters
  14- Speed and Duplex Configuration
  15- Additional Configurations
  16- Known Issues
  17- Support
  18
  19
  20In This Release
  21===============
  22
  23This file describes the Linux* Base Driver for the Intel(R) PRO/1000 Family
  24of Adapters.  This driver includes support for Itanium(R)2-based systems.
  25
  26For questions related to hardware requirements, refer to the documentation
  27supplied with your Intel PRO/1000 adapter. All hardware requirements listed
  28apply to use with Linux.
  29
  30The following features are now available in supported kernels:
  31 - Native VLANs
  32 - Channel Bonding (teaming)
  33 - SNMP
  34
  35Channel Bonding documentation can be found in the Linux kernel source:
  36/Documentation/networking/bonding.txt
  37
  38The driver information previously displayed in the /proc filesystem is not
  39supported in this release.  Alternatively, you can use ethtool (version 1.6
  40or later), lspci, and ifconfig to obtain the same information.
  41
  42Instructions on updating ethtool can be found in the section "Additional
  43Configurations" later in this document.
  44
  45NOTE: The Intel(R) 82562v 10/100 Network Connection only provides 10/100
  46support.
  47
  48
  49Identifying Your Adapter
  50========================
  51
  52For more information on how to identify your adapter, go to the Adapter &
  53Driver ID Guide at:
  54
  55    http://support.intel.com/support/network/adapter/pro100/21397.htm
  56
  57For the latest Intel network drivers for Linux, refer to the following
  58website.  In the search field, enter your adapter name or type, or use the
  59networking link on the left to search for your adapter:
  60
  61    http://downloadfinder.intel.com/scripts-df/support_intel.asp
  62
  63
  64Command Line Parameters
  65=======================
  66
  67If the driver is built as a module, the  following optional parameters
  68are used by entering them on the command line with the modprobe command
  69using this syntax:
  70
  71     modprobe e1000 [<option>=<VAL1>,<VAL2>,...]
  72
  73For example, with two PRO/1000 PCI adapters, entering:
  74
  75     modprobe e1000 TxDescriptors=80,128
  76
  77loads the e1000 driver with 80 TX descriptors for the first adapter and
  78128 TX descriptors for the second adapter.
  79
  80The default value for each parameter is generally the recommended setting,
  81unless otherwise noted.
  82
  83NOTES:  For more information about the AutoNeg, Duplex, and Speed
  84        parameters, see the "Speed and Duplex Configuration" section in
  85        this document.
  86
  87        For more information about the InterruptThrottleRate,
  88        RxIntDelay, TxIntDelay, RxAbsIntDelay, and TxAbsIntDelay
  89        parameters, see the application note at:
  90        http://www.intel.com/design/network/applnots/ap450.htm
  91
  92        A descriptor describes a data buffer and attributes related to
  93        the data buffer.  This information is accessed by the hardware.
  94
  95
  96AutoNeg
  97-------
  98(Supported only on adapters with copper connections)
  99Valid Range:   0x01-0x0F, 0x20-0x2F
 100Default Value: 0x2F
 101
 102This parameter is a bit-mask that specifies the speed and duplex settings
 103advertised by the adapter.  When this parameter is used, the Speed and
 104Duplex parameters must not be specified.
 105
 106NOTE:  Refer to the Speed and Duplex section of this readme for more
 107       information on the AutoNeg parameter.
 108
 109
 110Duplex
 111------
 112(Supported only on adapters with copper connections)
 113Valid Range:   0-2 (0=auto-negotiate, 1=half, 2=full)
 114Default Value: 0
 115
 116This defines the direction in which data is allowed to flow.  Can be
 117either one or two-directional.  If both Duplex and the link partner are
 118set to auto-negotiate, the board auto-detects the correct duplex.  If the
 119link partner is forced (either full or half), Duplex defaults to half-
 120duplex.
 121
 122
 123FlowControl
 124-----------
 125Valid Range:   0-3 (0=none, 1=Rx only, 2=Tx only, 3=Rx&Tx)
 126Default Value: Reads flow control settings from the EEPROM
 127
 128This parameter controls the automatic generation(Tx) and response(Rx)
 129to Ethernet PAUSE frames.
 130
 131
 132InterruptThrottleRate
 133---------------------
 134(not supported on Intel(R) 82542, 82543 or 82544-based adapters)
 135Valid Range:   0,1,3,100-100000 (0=off, 1=dynamic, 3=dynamic conservative)
 136Default Value: 3
 137
 138The driver can limit the amount of interrupts per second that the adapter
 139will generate for incoming packets. It does this by writing a value to the 
 140adapter that is based on the maximum amount of interrupts that the adapter 
 141will generate per second.
 142
 143Setting InterruptThrottleRate to a value greater or equal to 100
 144will program the adapter to send out a maximum of that many interrupts
 145per second, even if more packets have come in. This reduces interrupt
 146load on the system and can lower CPU utilization under heavy load,
 147but will increase latency as packets are not processed as quickly.
 148
 149The default behaviour of the driver previously assumed a static 
 150InterruptThrottleRate value of 8000, providing a good fallback value for 
 151all traffic types,but lacking in small packet performance and latency. 
 152The hardware can handle many more small packets per second however, and 
 153for this reason an adaptive interrupt moderation algorithm was implemented.
 154
 155Since 7.3.x, the driver has two adaptive modes (setting 1 or 3) in which
 156it dynamically adjusts the InterruptThrottleRate value based on the traffic 
 157that it receives. After determining the type of incoming traffic in the last
 158timeframe, it will adjust the InterruptThrottleRate to an appropriate value 
 159for that traffic.
 160
 161The algorithm classifies the incoming traffic every interval into
 162classes.  Once the class is determined, the InterruptThrottleRate value is 
 163adjusted to suit that traffic type the best. There are three classes defined: 
 164"Bulk traffic", for large amounts of packets of normal size; "Low latency",
 165for small amounts of traffic and/or a significant percentage of small
 166packets; and "Lowest latency", for almost completely small packets or 
 167minimal traffic.
 168
 169In dynamic conservative mode, the InterruptThrottleRate value is set to 4000 
 170for traffic that falls in class "Bulk traffic". If traffic falls in the "Low 
 171latency" or "Lowest latency" class, the InterruptThrottleRate is increased 
 172stepwise to 20000. This default mode is suitable for most applications.
 173
 174For situations where low latency is vital such as cluster or
 175grid computing, the algorithm can reduce latency even more when
 176InterruptThrottleRate is set to mode 1. In this mode, which operates
 177the same as mode 3, the InterruptThrottleRate will be increased stepwise to 
 17870000 for traffic in class "Lowest latency".
 179
 180Setting InterruptThrottleRate to 0 turns off any interrupt moderation
 181and may improve small packet latency, but is generally not suitable
 182for bulk throughput traffic.
 183
 184NOTE:  InterruptThrottleRate takes precedence over the TxAbsIntDelay and
 185       RxAbsIntDelay parameters.  In other words, minimizing the receive
 186       and/or transmit absolute delays does not force the controller to
 187       generate more interrupts than what the Interrupt Throttle Rate
 188       allows.
 189
 190CAUTION:  If you are using the Intel(R) PRO/1000 CT Network Connection
 191          (controller 82547), setting InterruptThrottleRate to a value
 192          greater than 75,000, may hang (stop transmitting) adapters
 193          under certain network conditions.  If this occurs a NETDEV
 194          WATCHDOG message is logged in the system event log.  In
 195          addition, the controller is automatically reset, restoring
 196          the network connection.  To eliminate the potential for the
 197          hang, ensure that InterruptThrottleRate is set no greater
 198          than 75,000 and is not set to 0.
 199
 200NOTE:  When e1000 is loaded with default settings and multiple adapters
 201       are in use simultaneously, the CPU utilization may increase non-
 202       linearly.  In order to limit the CPU utilization without impacting
 203       the overall throughput, we recommend that you load the driver as
 204       follows:
 205
 206           modprobe e1000 InterruptThrottleRate=3000,3000,3000
 207
 208       This sets the InterruptThrottleRate to 3000 interrupts/sec for
 209       the first, second, and third instances of the driver.  The range
 210       of 2000 to 3000 interrupts per second works on a majority of
 211       systems and is a good starting point, but the optimal value will
 212       be platform-specific.  If CPU utilization is not a concern, use
 213       RX_POLLING (NAPI) and default driver settings.
 214
 215
 216
 217RxDescriptors
 218-------------
 219Valid Range:   80-256 for 82542 and 82543-based adapters
 220               80-4096 for all other supported adapters
 221Default Value: 256
 222
 223This value specifies the number of receive buffer descriptors allocated
 224by the driver.  Increasing this value allows the driver to buffer more
 225incoming packets, at the expense of increased system memory utilization.
 226
 227Each descriptor is 16 bytes.  A receive buffer is also allocated for each
 228descriptor and can be either 2048, 4096, 8192, or 16384 bytes, depending 
 229on the MTU setting. The maximum MTU size is 16110.
 230
 231NOTE:  MTU designates the frame size.  It only needs to be set for Jumbo 
 232       Frames.  Depending on the available system resources, the request 
 233       for a higher number of receive descriptors may be denied.  In this 
 234       case, use a lower number.
 235
 236
 237RxIntDelay
 238----------
 239Valid Range:   0-65535 (0=off)
 240Default Value: 0
 241
 242This value delays the generation of receive interrupts in units of 1.024
 243microseconds.  Receive interrupt reduction can improve CPU efficiency if
 244properly tuned for specific network traffic.  Increasing this value adds
 245extra latency to frame reception and can end up decreasing the throughput
 246of TCP traffic.  If the system is reporting dropped receives, this value
 247may be set too high, causing the driver to run out of available receive
 248descriptors.
 249
 250CAUTION:  When setting RxIntDelay to a value other than 0, adapters may
 251          hang (stop transmitting) under certain network conditions.  If
 252          this occurs a NETDEV WATCHDOG message is logged in the system
 253          event log.  In addition, the controller is automatically reset,
 254          restoring the network connection.  To eliminate the potential
 255          for the hang ensure that RxIntDelay is set to 0.
 256
 257
 258RxAbsIntDelay
 259-------------
 260(This parameter is supported only on 82540, 82545 and later adapters.)
 261Valid Range:   0-65535 (0=off)
 262Default Value: 128
 263
 264This value, in units of 1.024 microseconds, limits the delay in which a
 265receive interrupt is generated.  Useful only if RxIntDelay is non-zero,
 266this value ensures that an interrupt is generated after the initial
 267packet is received within the set amount of time.  Proper tuning,
 268along with RxIntDelay, may improve traffic throughput in specific network
 269conditions.
 270
 271
 272Speed
 273-----
 274(This parameter is supported only on adapters with copper connections.)
 275Valid Settings: 0, 10, 100, 1000
 276Default Value:  0 (auto-negotiate at all supported speeds)
 277
 278Speed forces the line speed to the specified value in megabits per second
 279(Mbps).  If this parameter is not specified or is set to 0 and the link
 280partner is set to auto-negotiate, the board will auto-detect the correct
 281speed.  Duplex should also be set when Speed is set to either 10 or 100.
 282
 283
 284TxDescriptors
 285-------------
 286Valid Range:   80-256 for 82542 and 82543-based adapters
 287               80-4096 for all other supported adapters
 288Default Value: 256
 289
 290This value is the number of transmit descriptors allocated by the driver.
 291Increasing this value allows the driver to queue more transmits.  Each
 292descriptor is 16 bytes.
 293
 294NOTE:  Depending on the available system resources, the request for a
 295       higher number of transmit descriptors may be denied.  In this case,
 296       use a lower number.
 297
 298
 299TxIntDelay
 300----------
 301Valid Range:   0-65535 (0=off)
 302Default Value: 64
 303
 304This value delays the generation of transmit interrupts in units of
 3051.024 microseconds.  Transmit interrupt reduction can improve CPU
 306efficiency if properly tuned for specific network traffic.  If the
 307system is reporting dropped transmits, this value may be set too high
 308causing the driver to run out of available transmit descriptors.
 309
 310
 311TxAbsIntDelay
 312-------------
 313(This parameter is supported only on 82540, 82545 and later adapters.)
 314Valid Range:   0-65535 (0=off)
 315Default Value: 64
 316
 317This value, in units of 1.024 microseconds, limits the delay in which a
 318transmit interrupt is generated.  Useful only if TxIntDelay is non-zero,
 319this value ensures that an interrupt is generated after the initial
 320packet is sent on the wire within the set amount of time.  Proper tuning,
 321along with TxIntDelay, may improve traffic throughput in specific
 322network conditions.
 323
 324XsumRX
 325------
 326(This parameter is NOT supported on the 82542-based adapter.)
 327Valid Range:   0-1
 328Default Value: 1
 329
 330A value of '1' indicates that the driver should enable IP checksum
 331offload for received packets (both UDP and TCP) to the adapter hardware.
 332
 333
 334Speed and Duplex Configuration
 335==============================
 336
 337Three keywords are used to control the speed and duplex configuration.
 338These keywords are Speed, Duplex, and AutoNeg.
 339
 340If the board uses a fiber interface, these keywords are ignored, and the
 341fiber interface board only links at 1000 Mbps full-duplex.
 342
 343For copper-based boards, the keywords interact as follows:
 344
 345  The default operation is auto-negotiate.  The board advertises all
 346  supported speed and duplex combinations, and it links at the highest
 347  common speed and duplex mode IF the link partner is set to auto-negotiate.
 348
 349  If Speed = 1000, limited auto-negotiation is enabled and only 1000 Mbps
 350  is advertised (The 1000BaseT spec requires auto-negotiation.)
 351
 352  If Speed = 10 or 100, then both Speed and Duplex should be set.  Auto-
 353  negotiation is disabled, and the AutoNeg parameter is ignored.  Partner
 354  SHOULD also be forced.
 355
 356The AutoNeg parameter is used when more control is required over the
 357auto-negotiation process.  It should be used when you wish to control which
 358speed and duplex combinations are advertised during the auto-negotiation
 359process.
 360
 361The parameter may be specified as either a decimal or hexadecimal value as
 362determined by the bitmap below.
 363
 364Bit position   7      6      5       4       3      2      1       0
 365Decimal Value  128    64     32      16      8      4      2       1
 366Hex value      80     40     20      10      8      4      2       1
 367Speed (Mbps)   N/A    N/A    1000    N/A     100    100    10      10
 368Duplex                       Full            Full   Half   Full    Half
 369
 370Some examples of using AutoNeg:
 371
 372  modprobe e1000 AutoNeg=0x01 (Restricts autonegotiation to 10 Half)
 373  modprobe e1000 AutoNeg=1 (Same as above)
 374  modprobe e1000 AutoNeg=0x02 (Restricts autonegotiation to 10 Full)
 375  modprobe e1000 AutoNeg=0x03 (Restricts autonegotiation to 10 Half or 10 Full)
 376  modprobe e1000 AutoNeg=0x04 (Restricts autonegotiation to 100 Half)
 377  modprobe e1000 AutoNeg=0x05 (Restricts autonegotiation to 10 Half or 100
 378  Half)
 379  modprobe e1000 AutoNeg=0x020 (Restricts autonegotiation to 1000 Full)
 380  modprobe e1000 AutoNeg=32 (Same as above)
 381
 382Note that when this parameter is used, Speed and Duplex must not be specified.
 383
 384If the link partner is forced to a specific speed and duplex, then this
 385parameter should not be used.  Instead, use the Speed and Duplex parameters
 386previously mentioned to force the adapter to the same speed and duplex.
 387
 388
 389Additional Configurations
 390=========================
 391
 392  Configuring the Driver on Different Distributions
 393  -------------------------------------------------
 394  Configuring a network driver to load properly when the system is started
 395  is distribution dependent.  Typically, the configuration process involves
 396  adding an alias line to /etc/modules.conf or /etc/modprobe.conf as well
 397  as editing other system startup scripts and/or configuration files.  Many
 398  popular Linux distributions ship with tools to make these changes for you.
 399  To learn the proper way to configure a network device for your system,
 400  refer to your distribution documentation.  If during this process you are
 401  asked for the driver or module name, the name for the Linux Base Driver
 402  for the Intel(R) PRO/1000 Family of Adapters is e1000.
 403
 404  As an example, if you install the e1000 driver for two PRO/1000 adapters
 405  (eth0 and eth1) and set the speed and duplex to 10full and 100half, add
 406  the following to modules.conf or or modprobe.conf:
 407
 408       alias eth0 e1000
 409       alias eth1 e1000
 410       options e1000 Speed=10,100 Duplex=2,1
 411
 412  Viewing Link Messages
 413  ---------------------
 414  Link messages will not be displayed to the console if the distribution is
 415  restricting system messages.  In order to see network driver link messages
 416  on your console, set dmesg to eight by entering the following:
 417
 418       dmesg -n 8
 419
 420  NOTE: This setting is not saved across reboots.
 421
 422  Jumbo Frames
 423  ------------
 424  Jumbo Frames support is enabled by changing the MTU to a value larger than
 425  the default of 1500.  Use the ifconfig command to increase the MTU size.
 426  For example:
 427
 428       ifconfig eth<x> mtu 9000 up
 429
 430  This setting is not saved across reboots.  It can be made permanent if
 431  you add:
 432
 433       MTU=9000
 434
 435   to the file /etc/sysconfig/network-scripts/ifcfg-eth<x>.  This example
 436   applies to the Red Hat distributions; other distributions may store this
 437   setting in a different location.
 438
 439  Notes:
 440
 441  - To enable Jumbo Frames, increase the MTU size on the interface beyond
 442    1500.
 443
 444  - The maximum MTU setting for Jumbo Frames is 16110.  This value coincides
 445    with the maximum Jumbo Frames size of 16128.
 446
 447  - Using Jumbo Frames at 10 or 100 Mbps may result in poor performance or
 448    loss of link.
 449
 450  - Some Intel gigabit adapters that support Jumbo Frames have a frame size
 451    limit of 9238 bytes, with a corresponding MTU size limit of 9216 bytes.
 452    The adapters with this limitation are based on the Intel(R) 82571EB,
 453    82572EI, 82573L and 80003ES2LAN controller.  These correspond to the
 454    following product names:
 455     Intel(R) PRO/1000 PT Server Adapter
 456     Intel(R) PRO/1000 PT Desktop Adapter
 457     Intel(R) PRO/1000 PT Network Connection
 458     Intel(R) PRO/1000 PT Dual Port Server Adapter
 459     Intel(R) PRO/1000 PT Dual Port Network Connection
 460     Intel(R) PRO/1000 PF Server Adapter
 461     Intel(R) PRO/1000 PF Network Connection
 462     Intel(R) PRO/1000 PF Dual Port Server Adapter
 463     Intel(R) PRO/1000 PB Server Connection
 464     Intel(R) PRO/1000 PL Network Connection
 465     Intel(R) PRO/1000 EB Network Connection with I/O Acceleration
 466     Intel(R) PRO/1000 EB Backplane Connection with I/O Acceleration
 467     Intel(R) PRO/1000 PT Quad Port Server Adapter
 468
 469  - Adapters based on the Intel(R) 82542 and 82573V/E controller do not
 470    support Jumbo Frames. These correspond to the following product names:
 471     Intel(R) PRO/1000 Gigabit Server Adapter
 472     Intel(R) PRO/1000 PM Network Connection
 473
 474  - The following adapters do not support Jumbo Frames:
 475     Intel(R) 82562V 10/100 Network Connection
 476     Intel(R) 82566DM Gigabit Network Connection
 477     Intel(R) 82566DC Gigabit Network Connection
 478     Intel(R) 82566MM Gigabit Network Connection
 479     Intel(R) 82566MC Gigabit Network Connection
 480     Intel(R) 82562GT 10/100 Network Connection
 481     Intel(R) 82562G 10/100 Network Connection
 482
 483
 484  Ethtool
 485  -------
 486  The driver utilizes the ethtool interface for driver configuration and
 487  diagnostics, as well as displaying statistical information.  Ethtool
 488  version 1.6 or later is required for this functionality.
 489
 490  The latest release of ethtool can be found from
 491  http://sourceforge.net/projects/gkernel.
 492
 493  NOTE: Ethtool 1.6 only supports a limited set of ethtool options.  Support
 494  for a more complete ethtool feature set can be enabled by upgrading
 495  ethtool to ethtool-1.8.1.
 496
 497  Enabling Wake on LAN* (WoL)
 498  ---------------------------
 499  WoL is configured through the Ethtool* utility.  Ethtool is included with
 500  all versions of Red Hat after Red Hat 7.2.  For other Linux distributions,
 501  download and install Ethtool from the following website:
 502  http://sourceforge.net/projects/gkernel.
 503
 504  For instructions on enabling WoL with Ethtool, refer to the website listed
 505  above.
 506
 507  WoL will be enabled on the system during the next shut down or reboot.
 508  For this driver version, in order to enable WoL, the e1000 driver must be
 509  loaded when shutting down or rebooting the system.
 510
 511  Wake On LAN is only supported on port A for the following devices:
 512  Intel(R) PRO/1000 PT Dual Port Network Connection
 513  Intel(R) PRO/1000 PT Dual Port Server Connection
 514  Intel(R) PRO/1000 PT Dual Port Server Adapter
 515  Intel(R) PRO/1000 PF Dual Port Server Adapter
 516  Intel(R) PRO/1000 PT Quad Port Server Adapter
 517
 518  NAPI
 519  ----
 520  NAPI (Rx polling mode) is enabled in the e1000 driver.
 521
 522  See www.cyberus.ca/~hadi/usenix-paper.tgz for more information on NAPI.
 523
 524
 525Known Issues
 526============
 527
 528Dropped Receive Packets on Half-duplex 10/100 Networks
 529------------------------------------------------------
 530If you have an Intel PCI Express adapter running at 10mbps or 100mbps, half-
 531duplex, you may observe occasional dropped receive packets.  There are no
 532workarounds for this problem in this network configuration.  The network must
 533be updated to operate in full-duplex, and/or 1000mbps only.
 534
 535Jumbo Frames System Requirement
 536-------------------------------
 537Memory allocation failures have been observed on Linux systems with 64 MB
 538of RAM or less that are running Jumbo Frames.  If you are using Jumbo
 539Frames, your system may require more than the advertised minimum
 540requirement of 64 MB of system memory.
 541
 542Performance Degradation with Jumbo Frames
 543-----------------------------------------
 544Degradation in throughput performance may be observed in some Jumbo frames
 545environments.  If this is observed, increasing the application's socket
 546buffer size and/or increasing the /proc/sys/net/ipv4/tcp_*mem entry values
 547may help.  See the specific application manual and
 548/usr/src/linux*/Documentation/
 549networking/ip-sysctl.txt for more details.
 550
 551Jumbo Frames on Foundry BigIron 8000 switch
 552-------------------------------------------
 553There is a known issue using Jumbo frames when connected to a Foundry
 554BigIron 8000 switch.  This is a 3rd party limitation.  If you experience
 555loss of packets, lower the MTU size.
 556
 557Allocating Rx Buffers when Using Jumbo Frames 
 558---------------------------------------------
 559Allocating Rx buffers when using Jumbo Frames on 2.6.x kernels may fail if 
 560the available memory is heavily fragmented. This issue may be seen with PCI-X 
 561adapters or with packet split disabled. This can be reduced or eliminated 
 562by changing the amount of available memory for receive buffer allocation, by
 563increasing /proc/sys/vm/min_free_kbytes. 
 564
 565Multiple Interfaces on Same Ethernet Broadcast Network
 566------------------------------------------------------
 567Due to the default ARP behavior on Linux, it is not possible to have
 568one system on two IP networks in the same Ethernet broadcast domain
 569(non-partitioned switch) behave as expected.  All Ethernet interfaces
 570will respond to IP traffic for any IP address assigned to the system.
 571This results in unbalanced receive traffic.
 572
 573If you have multiple interfaces in a server, either turn on ARP
 574filtering by entering:
 575
 576    echo 1 > /proc/sys/net/ipv4/conf/all/arp_filter
 577(this only works if your kernel's version is higher than 2.4.5),
 578
 579NOTE: This setting is not saved across reboots.  The configuration
 580change can be made permanent by adding the line:
 581    net.ipv4.conf.all.arp_filter = 1
 582to the file /etc/sysctl.conf
 583
 584      or,
 585
 586install the interfaces in separate broadcast domains (either in
 587different switches or in a switch partitioned to VLANs).
 588
 58982541/82547 can't link or are slow to link with some link partners
 590-----------------------------------------------------------------
 591There is a known compatibility issue with 82541/82547 and some
 592low-end switches where the link will not be established, or will
 593be slow to establish.  In particular, these switches are known to
 594be incompatible with 82541/82547:
 595
 596    Planex FXG-08TE
 597    I-O Data ETG-SH8
 598
 599To workaround this issue, the driver can be compiled with an override
 600of the PHY's master/slave setting.  Forcing master or forcing slave
 601mode will improve time-to-link.
 602
 603    # make CFLAGS_EXTRA=-DE1000_MASTER_SLAVE=<n>
 604
 605Where <n> is:
 606
 607    0 = Hardware default
 608    1 = Master mode
 609    2 = Slave mode
 610    3 = Auto master/slave
 611
 612Disable rx flow control with ethtool
 613------------------------------------
 614In order to disable receive flow control using ethtool, you must turn
 615off auto-negotiation on the same command line.
 616
 617For example:
 618
 619   ethtool -A eth? autoneg off rx off
 620
 621Unplugging network cable while ethtool -p is running
 622----------------------------------------------------
 623In kernel versions 2.5.50 and later (including 2.6 kernel), unplugging
 624the network cable while ethtool -p is running will cause the system to
 625become unresponsive to keyboard commands, except for control-alt-delete.
 626Restarting the system appears to be the only remedy.
 627
 628
 629Support
 630=======
 631
 632For general information, go to the Intel support website at:
 633
 634    http://support.intel.com
 635
 636or the Intel Wired Networking project hosted by Sourceforge at:
 637
 638    http://sourceforge.net/projects/e1000
 639
 640If an issue is identified with the released source code on the supported
 641kernel with a supported adapter, email the specific information related
 642to the issue to e1000-devel@lists.sf.net
 643
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.