Ignore:
Timestamp:
Sep 24, 2013, 11:53:17 AM (11 years ago)
Author:
William Harrington <kb0iic@…>
Children:
2e9ccbe
Parents:
111b12a
Message:

Prepare for CLFS-2.0.0 release.

File:
1 moved

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  • BOOK/bootscripts/common/udev.xml

    r111b12a r76b06f6  
    66]>
    77
    8 <sect1 id="ch-scripts-eudev">
    9   <?dbhtml filename="eudev.html"?>
     8<sect1 id="ch-scripts-udev">
     9  <?dbhtml filename="udev.html"?>
    1010
    1111  <title>Device and Module Handling on a CLFS System</title>
    1212
    13   <indexterm zone="ch-scripts-eudev">
    14     <primary sortas="a-Eudev">Eudev</primary>
     13  <indexterm zone="ch-scripts-udev">
     14    <primary sortas="a-Udev">Udev</primary>
    1515    <secondary>usage</secondary>
    1616  </indexterm>
    1717
    18   <para>In <xref linkend="chapter-building-system"/>, we installed the Eudev
     18  <para>In <xref linkend="chapter-building-system"/>, we installed the Udev
    1919  package. Before we go into the details regarding how this works,
    2020  a brief history of previous methods of handling devices is in
     
    3030  the world.</para>
    3131
    32   <para>Using the Eudev method, only those devices which are detected by the
     32  <para>Using the Udev method, only those devices which are detected by the
    3333  kernel get device nodes created for them. Because these device nodes will be
    3434  created each time the system boots, they will be stored on a <systemitem
     
    7171
    7272  <sect2>
    73     <title>Eudev Implementation</title>
     73    <title>Udev Implementation</title>
    7474
    7575    <sect3>
     
    9393
    9494    <sect3>
    95       <title>Eudev Bootscript</title>
     95      <title>Udev Bootscript</title>
    9696
    9797      <para>The <command>S10udev</command> initscript takes care of creating
     
    109109      class="directory">/lib/udev/devices</filename> also provides an easy
    110110      workaround for devices that are not supported by the dynamic device
    111       handling infrastructure. The bootscript then starts the Eudev daemon,
     111      handling infrastructure. The bootscript then starts the Udev daemon,
    112112      <command>udevd</command>, which will act on any uevents it receives.
    113113      Finally, the bootscript forces the kernel to replay uevents for any
     
    120120      <title>Device Node Creation</title>
    121121
    122       <para>To obtain the right major and minor number for a device, Eudev relies
     122      <para>To obtain the right major and minor number for a device, Udev relies
    123123      on the information provided by <systemitem
    124124      class="filesystem">sysfs</systemitem> in <filename
     
    134134      <command>udevd</command> can't find a rule for the device it is creating,
    135135      it will default permissions to <emphasis>660</emphasis> and ownership to
    136       <emphasis>root:root</emphasis>. Documentation on the syntax of the Eudev
     136      <emphasis>root:root</emphasis>. Documentation on the syntax of the Udev
    137137      rules configuration files is available in
    138138      <filename>/usr/share/doc/udev/writing_udev_rules/index.html</filename></para>
     
    155155      might contain the string
    156156      <quote>pci:v00001319d00000801sv00001319sd00001319bc04sc01i00</quote>.
    157       The default rules provided by Eudev will cause <command>udevd</command>
     157      The default rules provided by Udev will cause <command>udevd</command>
    158158      to call out to <command>/sbin/modprobe</command> with the contents of the
    159159      <envar>MODALIAS</envar> uevent environment variable (that should be the
     
    194194      <title>A kernel module is not loaded automatically</title>
    195195
    196       <para>Eudev will only load a module if it has a bus-specific alias and the
     196      <para>Udev will only load a module if it has a bus-specific alias and the
    197197      bus driver properly exports the necessary aliases to <systemitem
    198198      class="filesystem">sysfs</systemitem>. In other cases, one should
    199       arrange module loading by other means. With Linux-&linux-version;, Eudev is
     199      arrange module loading by other means. With Linux-&linux-version;, Udev is
    200200      known to load properly-written drivers for INPUT, IDE, PCI, USB, SCSI,
    201201      SERIO and FireWire devices.</para>
    202202
    203203      <para>To determine if the device driver you require has the necessary
    204       support for Eudev, run <command>modinfo</command> with the module name as
     204      support for Udev, run <command>modinfo</command> with the module name as
    205205      the argument.  Now try locating the device directory under
    206206      <filename class="directory">/sys/bus</filename> and check whether there is
     
    210210      class="filesystem">sysfs</systemitem>, the driver supports the device and
    211211      can talk to it directly, but doesn't have the alias, it is a bug in the
    212       driver. Load the driver without the help from Eudev and expect the issue
     212      driver. Load the driver without the help from Udev and expect the issue
    213213      to be fixed later.</para>
    214214
     
    219219      busses. Expect this issue to be fixed in later kernel versions.</para>
    220220
    221       <para>Eudev is not intended to load <quote>wrapper</quote> drivers such as
     221      <para>Udev is not intended to load <quote>wrapper</quote> drivers such as
    222222      <emphasis>snd-pcm-oss</emphasis> and non-hardware drivers such as
    223223      <emphasis>loop</emphasis> at all.</para>
     
    226226
    227227    <sect3>
    228       <title>A kernel module is not loaded automatically, and Eudev is not
     228      <title>A kernel module is not loaded automatically, and Udev is not
    229229      intended to load it</title>
    230230
     
    233233      enhances the functionality of <emphasis>snd-pcm</emphasis> by making the
    234234      sound cards available to OSS applications), configure
    235       <command>modprobe</command> to load the wrapper after Eudev loads the
     235      <command>modprobe</command> to load the wrapper after Udev loads the
    236236      wrapped module. To do this, add an <quote>install</quote> line in
    237237      <filename>/etc/modprobe.conf</filename>. For example:</para>
     
    249249
    250250    <sect3>
    251       <title>Eudev loads some unwanted module</title>
     251      <title>Udev loads some unwanted module</title>
    252252
    253253      <para>Either don't build the module, or blacklist it in
     
    263263
    264264    <sect3>
    265       <title>Eudev creates a device incorrectly, or makes a wrong symlink</title>
     265      <title>Udev creates a device incorrectly, or makes a wrong symlink</title>
    266266
    267267      <para>This usually happens if a rule unexpectedly matches a device. For
     
    274274
    275275    <sect3>
    276       <title>Eudev rule works unreliably</title>
     276      <title>Udev rule works unreliably</title>
    277277
    278278      <para>This may be another manifestation of the previous problem. If not,
     
    288288
    289289    <sect3>
    290       <title>Eudev does not create a device</title>
     290      <title>Udev does not create a device</title>
    291291
    292292      <para>Further text assumes that the driver is built statically into the
    293293      kernel or already loaded as a module, and that you have already checked
    294       that Eudev doesn't create a misnamed device.</para>
    295 
    296       <para>Eudev has no information needed to create a device node if a kernel
     294      that Udev doesn't create a misnamed device.</para>
     295
     296      <para>Udev has no information needed to create a device node if a kernel
    297297      driver does not export its data to <systemitem
    298298      class="filesystem">sysfs</systemitem>.
     
    311311      <title>Device naming order changes randomly after rebooting</title>
    312312
    313       <para>This is due to the fact that Eudev, by design, handles uevents and
     313      <para>This is due to the fact that Udev, by design, handles uevents and
    314314      loads modules in parallel, and thus in an unpredictable order. This will
    315315      never be <quote>fixed</quote>. You should not rely upon the kernel device
    316316      names being stable. Instead, create your own rules that make symlinks with
    317317      stable names based on some stable attributes of the device, such as a
    318       serial number or the output of various *_id utilities installed by Eudev.
     318      serial number or the output of various *_id utilities installed by Udev.
    319319      See <xref linkend="ch-scripts-symlinks"/> and
    320320      <xref linkend="chapter-network"/> for examples.</para>
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