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