- Timestamp:
- Apr 26, 2014, 7:18:51 PM (11 years ago)
- Branches:
- clfs-3.0.0-systemd, clfs-3.0.0-sysvinit, master, systemd, sysvinit
- Children:
- ec9b2de
- Parents:
- de0df04
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BOOK/system-config/common/udev.xml
rde0df04 r416772a 93 93 94 94 <sect3> 95 <title>Udev Bootscript</title>96 97 <para>The <command>S10udev</command> initscript takes care of creating98 device nodes when Linux is booted. The script unsets the uevent handler99 from the default of <command>/sbin/hotplug</command>. This is done100 because the kernel no longer needs to call out to an external binary.101 Instead <command>udevd</command> will listen on a netlink socket for102 uevents that the kernel raises. Next, the bootscript copies any static103 device nodes that exist in <filename104 class="directory">/lib/udev/devices</filename> to <filename105 class="directory">/dev</filename>. This is necessary because some devices,106 directories, and symlinks are needed before the dynamic device handling107 processes are available during the early stages of booting a system.108 Creating static device nodes in <filename109 class="directory">/lib/udev/devices</filename> also provides an easy110 workaround for devices that are not supported by the dynamic device111 handling infrastructure. The bootscript then starts the Udev daemon,112 <command>udevd</command>, which will act on any uevents it receives.113 Finally, the bootscript forces the kernel to replay uevents for any114 devices that have already been registered and then waits for115 <command>udevd</command> to handle them.</para>116 117 </sect3>118 119 <sect3>120 95 <title>Device Node Creation</title> 121 96 … … 129 104 <emphasis>0</emphasis>. The names and permissions of the nodes created 130 105 under the <filename class="directory">/dev</filename> directory are 131 determined by rules specified in the files within the <filename 132 class="directory">/etc/udev/rules.d/</filename> directory. These are 133 numbered in a similar fashion to the CLFS-Bootscripts package. If 134 <command>udevd</command> can't find a rule for the device it is creating, 135 it will default permissions to <emphasis>660</emphasis> and ownership to 136 <emphasis>root:root</emphasis>. Documentation on the syntax of the Udev 137 rules configuration files is available in 138 <filename>/usr/share/doc/udev/writing_udev_rules/index.html</filename></para> 106 determined by rules specified in the files within the 107 <filename class="directory">/lib/udev/rules.d</filename> and <filename 108 class="directory">/etc/udev/rules.d/</filename> directories. These files 109 have names that start with numbers, and are evaluated in numerical order. 110 If <command>udevd</command> can't find a rule for the device it is 111 creating, it will default permissions to <emphasis>660</emphasis> and 112 ownership to <emphasis>root:root</emphasis>. </para> 139 113 140 114 </sect3> … … 234 208 sound cards available to OSS applications), configure 235 209 <command>modprobe</command> to load the wrapper after Udev loads the 236 wrapped module. To do this, add an <quote>install</quote> line in237 <filename>/etc/modprobe.conf</filename>. For example:</para>210 wrapped module. To do this, add an <quote>install</quote> line to a file 211 in <filename>/etc/modprobe.d</filename>. For example:</para> 238 212 239 213 <screen role="nodump"><literal>install snd-pcm /sbin/modprobe -i snd-pcm ; \ 240 214 /sbin/modprobe snd-pcm-oss ; true</literal></screen> 241 215 242 <para>If the module in question is not a wrapper and is useful by itself,243 configure the <command>S05modules</command> bootscript to load this244 module on system boot. To do this, add the module name to the245 <filename>/etc/sysconfig/modules</filename> file on a separate line.246 This works for wrapper modules too, but is suboptimal in that case.</para>247 248 216 </sect3> 249 217 … … 252 220 253 221 <para>Either don't build the module, or blacklist it in 254 <filename>/etc/modprobe. conf</filename> file as done with the222 <filename>/etc/modprobe.d</filename> file as done with the 255 223 <emphasis>forte</emphasis> module in the example below:</para> 256 224
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