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nightmorph 07/10/30 20:31:27 |
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|
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Modified: udev-guide.xml |
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Log: |
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added udev module order section, as suggested by zzam via email |
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|
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Revision Changes Path |
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1.44 xml/htdocs/doc/en/udev-guide.xml |
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|
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file : http://sources.gentoo.org/viewcvs.py/gentoo/xml/htdocs/doc/en/udev-guide.xml?rev=1.44&view=markup |
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plain: http://sources.gentoo.org/viewcvs.py/gentoo/xml/htdocs/doc/en/udev-guide.xml?rev=1.44&content-type=text/plain |
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diff : http://sources.gentoo.org/viewcvs.py/gentoo/xml/htdocs/doc/en/udev-guide.xml?r1=1.43&r2=1.44 |
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|
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Index: udev-guide.xml |
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=================================================================== |
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RCS file: /var/cvsroot/gentoo/xml/htdocs/doc/en/udev-guide.xml,v |
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retrieving revision 1.43 |
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retrieving revision 1.44 |
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diff -u -r1.43 -r1.44 |
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--- udev-guide.xml 18 Oct 2007 18:31:06 -0000 1.43 |
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+++ udev-guide.xml 30 Oct 2007 20:31:27 -0000 1.44 |
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@@ -1,6 +1,6 @@ |
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<?xml version='1.0' encoding="UTF-8"?> |
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<!DOCTYPE guide SYSTEM "/dtd/guide.dtd"> |
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-<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/udev-guide.xml,v 1.43 2007/10/18 18:31:06 nightmorph Exp $ --> |
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+<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/udev-guide.xml,v 1.44 2007/10/30 20:31:27 nightmorph Exp $ --> |
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|
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<guide link="/doc/en/udev-guide.xml"> |
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<title>Gentoo udev Guide</title> |
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@@ -11,6 +11,9 @@ |
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<author title="Contributor"> |
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<mail link="greg_g@g.o">Gregorio Guidi</mail> |
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</author> |
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+<author title="Editor"> |
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+ <mail link="nightmorph"/> |
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+</author> |
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|
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<abstract> |
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This document explains what udev is and how you can use udev to fit your needs. |
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@@ -20,8 +23,8 @@ |
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<!-- See http://creativecommons.org/licenses/by-sa/2.5 --> |
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<license/> |
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|
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-<version>0.32</version> |
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-<date>2007-08-02</date> |
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+<version>0.33</version> |
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+<date>2007-10-30</date> |
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|
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<chapter> |
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<title>What is udev?</title> |
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@@ -397,6 +400,61 @@ |
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</body> |
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</section> |
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<section> |
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+<title>udev loads modules in an unpredictable order</title> |
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+<body> |
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+ |
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+<p> |
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+Sometimes udev loads modules in an undesired, unpredictable, or seemingly random |
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+order. This is especially common for systems that have multiple devices of the |
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+same type, as well as multimedia devices. This can affect the assigned numbers |
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+of devices; for example, sound cards may sometimes swap numbers. |
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+</p> |
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+ |
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+<p> |
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+There are a few solutions to fix device numbers and/or module load order. |
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+Ideally, you can just use module parameters to specify your desired device |
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+number. Some modules, such as ALSA, include the "index" parameter. Modules that |
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+use the index parameter can be adjusted as shown. This example is for a system |
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+with two sound cards. The card with an index of 0 is designated as the first |
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+card. Once the parameters are changed, the module config files must be updated. |
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+</p> |
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+ |
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+<pre caption="Specifying module parameters"> |
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+# <i>echo "option snd-ice1724 index=0" >> /etc/modules.d/alsa</i> |
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+# <i>echo "option snd-ymfpci index=1" >> /etc/modules.d/alsa</i> |
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+# <i>update-modules</i> |
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+</pre> |
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+ |
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+<p> |
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+The above example is the preferred solution, but not all modules support |
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+parameters such as index. For these modules, you'll have to force the correct |
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+module load order. First, you must stop udev from autoloading the modules by |
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+blacklisting them. Be sure to use the exact name of the module being loaded. |
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+For PCI devices, you'll need to use the module names obtained from the output of |
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+<c>pcimodules</c>, available in the <c>pciutils</c> package. The following |
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+example uses DVB modules. |
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+</p> |
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+ |
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+<pre caption="Blacklisting modules"> |
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+# <i>echo "blacklist b2c2-flexcop-pci" >> /etc/modules.d/dvb</i> |
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+# <i>echo "blacklist budget" >> /etc/modules.d/dvb</i> |
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+# <i>update-modules</i> |
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+</pre> |
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+ |
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+<p> |
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+Next, load the modules in the correct order. Add them to |
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+<path>/etc/modules.autoload.d/kernel-2.6</path> <e>in the exact order you want |
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+them loaded</e>. |
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+</p> |
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+ |
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+<pre caption="Loading modules in the correct order"> |
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+# <i>echo "budget" >> /etc/modules.autoload.d/kernel-2.6</i> |
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+# <i>echo "b2c2-flexcop-pci" >> /etc/modules.autoload.d/kernel-2.6</i> |
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+</pre> |
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+ |
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+</body> |
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+</section> |
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+<section> |
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<title>Other issues</title> |
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<body> |
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-- |
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