source: postlfs/config/firmware.xml@ f3429309

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../../general.ent">
  %general-entities;
]>

<sect1 id="postlfs-firmware" xreflabel="About Firmware">
  <?dbhtml filename="firmware.html"?>

  <sect1info>
    <othername>$LastChangedBy$</othername>
    <date>$Date$</date>
  </sect1info>

  <title>About Firmware</title>

  <indexterm zone="postlfs-firmware">
    <primary sortas="e-lib-firmware">/lib/firmware</primary>
  </indexterm>

  <para> On some recent PCs it can be necessary, or desirable, to load firmware
  to make them work at their best. There is a directory, <filename
  class="directory">/lib/firmware</filename>, where the kernel or kernel
  drivers look for firmware images.</para>

  <para>Preparing firmware for multiple different machines, as a distro would
  do, is outside the scope of this book.</para>

  <para>Currently, most firmware can be found at a <userinput>git</userinput>
  repository: <ulink
  url="http://git.kernel.org/cgit/linux/kernel/git/firmware/linux-firmware.git/tree/"/>.
  For convenience, the LFS Project has created a mirror, updated daily, where
  these firmware files can be accessed via <userinput>wget</userinput> or a web
  browser at <ulink
  url="&sources-anduin-http;/linux-firmware/"/>.</para>

  <para>To get the firmware, either point a browser to one of the above
  repositories and then download the item(s) which you need, or install
  <userinput>git</userinput> and clone that repository.</para>

  <para>For some other firmware, particularly for Intel microcode and certain
  wifi devices, the needed firmware is not available in the above repository.
  Some of this will be addressed below, but a search of the Internet for needed
  firmware is sometimes necessary.</para>

  <para>Firmware files are conventionally referred to as blobs because you cannot
  determine what they will do. Note that firmware is distributed under various
  different licenses which do not permit disassembly or reverse-engineering.</para>

  <para>Firmware for PCs falls into four categories:</para>

  <itemizedlist spacing="compact">
    <listitem>
      <para>Updates to the CPU to work around errata, usually referred to as
       microcode.</para>
    </listitem>
    <listitem>
      <para>Firmware for video controllers. On x86 machines this seems to only
      apply to ATI devices : Radeons require firmware to be able to use KMS
      (kernel modesetting - the preferred option) as well as for Xorg. For
      earlier radeon chips (before the R600), the firmware is still in the
      kernel.</para>
    </listitem>
    <listitem>
      <para>Firmware updates for wired network ports. Mostly they work even
      without the updates, but one must assume that they will work better with
      the updated firmware.</para>
    </listitem>
    <listitem>
      <para>Firmware for other devices, such as wifi. These devices are not
      required for the PC to boot, but need the firmware before these devices
      can be used.</para>
    </listitem>
  </itemizedlist>

  <note><para>Although not needed to load a firmware blob, the following
  tools may be useful for determining, obtaining, or preparing the needed
  firmware in order to load it into the system:
    <xref linkend="cpio"/>,
    <xref linkend="git"/>,
    <xref linkend="pciutils"/>, and
    <xref linkend="wget"/></para></note>

  <para condition="html" role="usernotes">User Notes:
  <ulink url="&blfs-wiki;/aboutfirmware"/></para>

  <sect2 id="cpu-microcode">
    <title>Microcode updates for CPUs</title>

    <para>In general, microcode can be loaded by the BIOS or UEFI, and it might
    be updated by upgrading to a newer version of those. On linux, you can also
    load the microcode from the kernel if you are using an AMD family 10h or
    later processor (first introduced late 2007), or an intel processor from
    1998 and later (Pentium4, Core, etc), if updated microcode has been
    released. These updates only last until the machine is powered off, so they
    need to be applied on every boot.</para>

    <para>There are two ways of loading the microcode, described as 'early' and
    'late'. Early loading happens before userspace has been started, late
    loading happens when userspace has started. Not surprisingly, early loading
    is preferred, (see e.g. an explanatory comment in a kernel commit noted at
    <ulink url="https://lwn.net/Articles/530346/">x86/microcode: Early load
    microcode </ulink> on LWN.)  Indeed, it is needed to work around one
    particular erratum in early intel Haswell processors which had TSX enabled.
    (See <ulink
    url="http://www.anandtech.com/show/8376/intel-disables-tsx-instructions-erratum-found-in-haswell-haswelleep-broadwellyi/">
    Intel Disables TSX Instructions: Erratum Found in Haswell, Haswell-E/EP,
    Broadwell-Y</ulink>.) Without this update glibc can do the wrong thing in
    uncommon situations.</para>

    <para>It is much simpler to begin by building a kernel which boots on
    your hardware, try late microcode loading to see if there is an update (in
    many cases the BIOS or UEFI will have already applied any update), and then
    take the extra steps required for early loading.</para>

    <para>This means you will be reconfiguring your kernel if you use early
    loading, so keep the built source around to minimise what gets rebuilt, and
    if you are at all uncertain, add your own identifier (A,B, etc) to the end
    of the EXTRAVERSION in the kernel configuration, e.g. "EXTRAVERSION -A" if
    nothing was set.</para>

    <para>To confirm what processor(s) you have (if more than one, they will be
    identical) look in /proc/cpuinfo.</para>

    <sect3 id="intel-microcode">
      <title>Intel Microcode for the CPU</title>

      <bridgehead renderas="sect4">Required Package</bridgehead>
      <para role='required'>
         <ulink url='http://fedorahosted.org/released/microcode_ctl/'/></para>

      <para>For intel CPUs an extra package, microcode_ctl, is required. The
      package chosen is the version hosted at fedora &mdash; there is an
      alternative version at github from the same packager, but that still
      includes a redundant old version of an AMD microcode container, and also
      requires the unzip package.</para>

      <para>Download the latest version from the link above; when last checked,
      this was 2.1-7 and is updated when intel releases new microcode.</para>

      <para>This package reformats the microcode supplied by intel into a
      format which the kernel can apply. The program
      <userinput>intel-microcode2ucode</userinput> is built and invoked by the
      Makefile to create the individual firmware blobs, so there is no reason
      to install it.</para>

      <para>Begin by extracting the tarball and changing to the directory it created.
      Then change to the source diirectory and run:</para>

<screen><userinput>make</userinput></screen>

      <para>This creates various blobs with names in the form XX-YY-ZZ. Now you
      need to determine your processor's identity, to see if there is any
      microcode for it. Determine the decimal values of the cpu family, model
      and stepping by running:</para>

<screen><userinput>head -n7 /proc/cpuinfo</userinput></screen>

      <para>Now convert the cpu family, model and stepping to pairs of hexadecimal
      digits. For a SandyBridge i3-2120 (described as Intel(R) Core(TM) i3-2120
      CPU) the relevant values are cpu family 6, model 42, stepping 7 so in
      this case the required identification is 06-2a-07. A look at the blobs
      will show that there is one for this CPU (although it might
      have already been applied by the BIOS). If there is a blob for your
      system then test if it will be applied by copying it (replace &lt;XX-YY-ZZ&gt;
      by the identifier for your machine) to where the kernel can find it:</para>

<screen><userinput>mkdir -pv /lib/firmware/intel-ucode
cp -v &lt;XX-YY-ZZ&gt; /lib/firmware/intel-ucode</userinput></screen>

      <para>Now that the intel microcode has been prepared, use the following
      options when you configure the kernel to try late loading of the intel
      microcode:</para>

<screen><literal>Processor type and features  ---&gt;
  &lt;M&gt; CPU microcode loading support  [CONFIG_MICROCODE]
  [*]      Intel microcode loading support [CONFIG_MICROCODE_INTEL]</literal></screen>

      <para>After you have successfully booted the new system, use the command
      <userinput>dmesg | grep microcode</userinput> and study the results to
      see if the message new patch_level appears.  This example from the
      SandyBridge i3:</para>

<screen><literal>[    0.059906] perf_event_intel: PEBS disabled due to CPU errata, please upgrade microcode
[    2.603083] microcode: CPU0 sig=0x206a7, pf=0x2, revision=0x23
[    2.669378] microcode: CPU0 sig=0x206a7, pf=0x2, revision=0x23
[    2.669994] microcode: CPU0 updated to revision 0x29, date = 2013-06-12
[    2.670069] microcode: CPU1 sig=0x206a7, pf=0x2, revision=0x23
[    2.670139] microcode: CPU1 sig=0x206a7, pf=0x2, revision=0x23
[    2.670501] microcode: CPU1 updated to revision 0x29, date = 2013-06-12
[    2.670509] microcode: CPU2 sig=0x206a7, pf=0x2, revision=0x23
[    2.670540] microcode: CPU2 sig=0x206a7, pf=0x2, revision=0x23
[    2.670917] microcode: CPU2 updated to revision 0x29, date = 2013-06-12
[    2.670955] microcode: CPU3 sig=0x206a7, pf=0x2, revision=0x23
[    2.670988] microcode: CPU3 sig=0x206a7, pf=0x2, revision=0x23
[    2.671348] microcode: CPU3 updated to revision 0x29, date = 2013-06-12
[    2.671356] perf_event_intel: PEBS enabled due to microcode update
[    2.671412] microcode: Microcode Update Driver: v2.00 &lt;tigran@aivazian.fsnet.co.uk&gt;, Peter Oruba</literal></screen>

    <para>If the microcode was not updated, there is no new microcode for
    this system's processor. If it did get updated, you can now proceed to <xref
    linkend='early-microcode'/>.</para>

    </sect3>

    <sect3 id="and-microcode">
      <title>AMD Microcode for the CPU</title>

      <para>Begin by downloading a container of firmware for your CPU family
      from <ulink
      url='&sources-anduin-http;/linux-firmware/amd-ucode/'/>.
      The family is always specified in hex. Families 10h to 14h (16 to 20)
      are in microcode_amd.bin.  Families 15h and 16h have their own containers.
      Create the required directory and put the firmware you downloaded into
      it as the <systemitem class="username">root</systemitem> user:</para>

<screen><userinput>mkdir -pv /lib/firmware/amd-ucode
cp -v microcode_amd* /lib/firmware/amd-ucode</userinput></screen>

      <para>When you configure the kernel, use the following options to try
      late loading of AMD microcode:</para>

<screen><literal>Processor type and features  ---&gt;
  &lt;M&gt; CPU microcode loading support   [CONFIG_MICROCODE]
  [*]   AMD microcode loading support [CONFIG_MICROCODE_AMD]</literal></screen>

      <para>After you have successfully booted the new system, use the command
      <userinput>dmesg | grep microcode</userinput> and study the results to see
      if the message new patch_level appears, as in this example from an old
      Athlon(tm) II X2:</para>

<screen><literal>[    4.183907] microcode: CPU0: patch_level=0x010000b6
[    4.184271] microcode: CPU0: new patch_level=0x010000c8
[    4.184278] microcode: CPU1: patch_level=0x010000b6
[    4.184283] microcode: CPU1: new patch_level=0x010000c8
[    4.184359] microcode: Microcode Update Driver: v2.00 &lt;tigran@aivazian.fsnet.co.uk&gt;, Peter Oruba</literal></screen>

    <para>If the microcode was not updated, there is no new microcode for
    this system's processor. If it did get updated, you can now proceed to <xref
    linkend='early-microcode'/>.</para>

    </sect3>

    <sect3 id="early-microcode">
      <title>Early loading of microcode</title>

      <para>If you have established that updated microcode is available for
      your system, it is time to prepare it for early loading. This requires
      an additional package, <xref linkend='cpio'/>, as well as changes to
      the kernel config and the creation of an initrd which will need to be
      added to grub.cfg.</para>

      <para>It does not matter where you prepare the initrd, and once it is
      working you can apply the same initrd to later LFS systems or newer
      kernels on this same machine, at least until any newer microcode is
      released. Use the following commands:</para>

<screen><userinput>mkdir -p initrd/kernel/x86/microcode
cd initrd</userinput></screen>

      <para>For an AMD machine, use the following command (replace
      &lt;MYCONTAINER&gt; with the name of the container for your CPU's
      family):</para>

<screen><userinput>cp -v /lib/firmware/amd_ucode/&lt;MYCONTAINER&gt; kernel/x86/microcode/AuthenticAMD.bin</userinput></screen>

      <para>Or for an Intel machine copy the appropriate blob using this command:</para>

<screen><userinput>cp -v /lib/firmware/intel-ucode/&lt;XX-YY-ZZ&gt; kernel/x86/microcode/GenuineIntel.bin</userinput></screen>

      <para>Now prepare the initrd:</para>

<screen><userinput>find . | cpio -o -H newc &gt; /boot/microcode.img</userinput></screen>

      <para>You will now need to reconfigure and rebuild your kernel. It is
      safer to either add/change the EXTRAVERSION in the kernel's configuration
      and install the newer kernel with a new name, or else (unless you have a
      machine which requires an early firmware update) wait for the next
      SUBLEVEL kernel release so that you can fall back to the existing kernel
      in the event that something goes wrong.</para>

      <para>You will also need to add a new entry to /boot/grub/grub.cfg and
      here you should add a new line after the linux line within the stanza.
      If /boot is a separate mountpoint: </para>

<screen><userinput>initrd /microcode.img</userinput></screen>

      <para>or this if it is not:</para>

<screen><userinput>initrd /boot/microcode.img</userinput></screen>

      <para>You must also change the kernel config:</para>

<screen><literal>General Setup ---&gt;
  [y] Initial RAM filesystem and RAM disk (initramfs/initrd) support [CONFIG_BLK_DEV_INITRD]
  [y] CPU microcode loading support                                  [CONFIG_MICROCODE]</literal></screen>

      <para>Retain the setting for INTEL or AMD microcode. When you have saved
      the .config file, either CONFIG_MICROCODE_INTEL_EARLY=y or
      CONFIG_MICROCODE_AMD_EARLY=y should be set, together with
      CONFIG_MICROCODE_EARLY=y.</para>

      <para>When you have installed and booted this kernel, you should check
      the output of dmesg to confirm that the early load worked. The places and
      times where this happens are very different in AMD and Intel machines.
      First, an Intel example where a development kernel is being tested,
      showing that the first notification comes before the kernel version is
      mentioned:</para>

<screen><literal>[    0.000000] CPU0 microcode updated early to revision 0x29, date = 2013-06-12
[    0.000000] Linux version 4.0.0-rc6 (ken@jtm1) (gcc version 4.9.2 (GCC) )
               #3 SMP PREEMPT Mon Mar 30 21:26:02 BST 2015
[    0.000000] Command line: BOOT_IMAGE=/vmlinuz-4.0.0-rc6-sda13 root=/dev/sda13 ro
...
[    0.103091] CPU1 microcode updated early to revision 0x29, date = 2013-06-12
[    0.113241]  #2
[    0.134631]  #3
[    0.147821] x86: Booted up 1 node, 4 CPUs
[    0.147936] smpboot: Total of 4 processors activated (26338.66 BogoMIPS)
...
[    0.272643] microcode: CPU0 sig=0x206a7, pf=0x2, revision=0x29
[    0.272709] microcode: CPU1 sig=0x206a7, pf=0x2, revision=0x29
[    0.272775] microcode: CPU2 sig=0x206a7, pf=0x2, revision=0x29
[    0.272842] microcode: CPU3 sig=0x206a7, pf=0x2, revision=0x29
[    0.272941] microcode: Microcode Update Driver: v2.00 &lt;tigran@aivazian.fsnet.co.uk&gt;, Peter Oruba</literal></screen>

      <para>A second AMD example is where the machine was running a stable
      kernel on an older version of LFS. Note that here there is no mention of
      the previous microcode version &mdash; compare this output to the AMD
      late loading messages (above) from the same machine:</para>

<screen><literal>[    0.000000] Linux version 3.18.11 (ken@milliways) (gcc version 4.9.1 (GCC) )
               #4 SMP Thu Apr 9 21:51:05 BST 2015
[    0.000000] Command line: BOOT_IMAGE=/vmlinuz-3.18.11-sda5 root=/dev/sda5 video=800x600 ro
...
[    0.584009] Trying to unpack rootfs image as initramfs...
[    0.584092] microcode: updated early to new patch_level=0x010000c8
...
[    0.586733] microcode: CPU0: patch_level=0x010000c8
[    0.586778] microcode: CPU1: patch_level=0x010000c8
[    0.586866] microcode: Microcode Update Driver: v2.00 &lt;tigran@aivazian.fsnet.co.uk&gt;, Peter Oruba</literal></screen>

    </sect3>

  </sect2>

  <sect2 id="ati-video-firmware">
    <title>Firmware for ATI video chips (R600 and later)</title>

    <para>These instructions do NOT apply to old radeons before the R600
    family. For those, the firmware is in the kernel's <filename
    class='directory'>/lib/firmware/</filename> directory. Nor do they apply if
    you intend to avoid a graphical setup such as Xorg and are content to use
    the default 80x25 display rather than a framebuffer. </para>

    <para> Early radeon devices only needed a single 2K blob of firmware.
    Recent devices need several different blobs, and some of them are much
    bigger. The total size of the radeon firmware directory is over 500K &mdash; on a
    large modern system you can probably spare the space, but it is still
    redundant to install all the unused files each time you build a system.</para>

    <para>A better approach is to install <xref linkend='pciutils'/> and then
    use <userinput>lspci</userinput> to identify which VGA controller is
    installed.</para>

    <para>With that information, check the RadeonFeature page of the Xorg wiki
    for <ulink url="http://wiki.x.org/wiki/RadeonFeature/#index5h2">Decoder
    ring for engineering vs marketing names</ulink> to identify the family (you
    may need to know this for the Xorg driver in BLFS &mdash; Southern Islands and
    Sea Islands use the radeonsi driver) and the specific model.</para>

    <para>Now that you know which controller you are using, consult the
    <ulink url="https://wiki.gentoo.org/wiki/Radeon#Firmware">Radeon</ulink> page
    of the Gentoo wiki which has a table listing the required firmware blobs
    for the various chipsets. Note that Southern Islands and Sea Islands chips
    use different firmware for kernel 3.17 and later compared to earlier
    kernels. Identify and download the required blobs then install them:</para>

<screen><userinput>mkdir -pv /lib/firmware/radeon
cp -v &lt;YOUR_BLOBS&gt; /lib/firmware/radeon</userinput></screen>

    <para>There are actually two ways of installing this firmware. BLFS, in the
    'Kernel Configuration for additional firmware' section part of the <xref
    linkend="xorg-ati-driver"/> section  gives an example of compiling the
    firmware into the kernel - that is slightly faster to load, but uses more
    kernel memory. Here we will use the alternative method of making the radeon
    driver a module. In your kernel config set the following: </para>

<screen><literal>Device Drivers ---&gt;
  Graphics support ---&gt;
      Direct Rendering Manager ---&gt;
            &lt;*&gt; Direct Rendering Manager (XFree86 ... support)  [CONFIG_DRM]
            &lt;m&gt; ATI Radeon                                      [CONFIG_DRM_RADEON]</literal></screen>

    <para>Loading several large blobs from /lib/firmware takes a noticeable
    time, during which the screen will be blank. If you do not enable the
    penguin framebuffer logo, or change the console size by using a bigger
    font, that probably does not matter. If desired, you can slightly
    reduce the time if you follow the alternate method of specifying 'y' for
    CONFIG_DRM_RADEON covered in BLFS at the link above &mdash; you must specify each
    needed radeon blob if you do that.</para>

  </sect2>

  <sect2 id="nic-firmware">
    <title>Firmware for Network Interfaces</title>

    <para>The kernel likes to load firmware for some network drivers,
    particularly those from Realtek (the /lib/linux-firmware/rtl_nic/) directory,
    but they generally appear to work without it. Therefore, you can boot the
    kernel, check dmesg for messages about this missing firmware, and if
    necessary download the firmware and put it in the specified directory in
    /lib/firmware so that it will be found on subsequent boots. Note that with
    current kernels this works whether or not the driver is compiled in or
    built as a module, there is no need to build this firmware into the kernel.
    Here is an example where the R8169 driver has been compiled in but the
    firmware was not made available. Once the firmware had been provided, there
    was no mention of it on later boots. </para>

<screen><literal>dmesg | grep firmware | grep r8169
[    7.018028] r8169 0000:01:00.0: Direct firmware load for rtl_nic/rtl8168g-2.fw failed with error -2
[    7.018036] r8169 0000:01:00.0 eth0: unable to load firmware patch rtl_nic/rtl8168g-2.fw (-2)</literal></screen>

  </sect2>

  <sect2 id="other-firmware">
    <title>Firmware for Other Devices</title>

    <para> Identifying the correct firmware will typically require you to
    install <xref linkend='pciutils'/>, and then use
    <userinput>lspci</userinput> to identify the device. You should then search
    online to check which module it uses, which firmware, and where to obtain
    the firmware &mdash; not all of it is in linux-firmware.</para>

    <para>If possible, you should begin by using a wired connection when you
    first boot your LFS system. To use a wireless connection you will need to
    use a network tools such as <xref linkend='wireless_tools'/> and <xref
    linkend='wpa_supplicant'/>.</para>

    <para>Firmware may also be needed for other devices such as some SCSI
    controllers, bluetooth adaptors, or TV recorders. The same principles
    apply.</para>

  </sect2>

</sect1>