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diff --git a/abs/core-testing/udev/readme-udev-arch.txt b/abs/core-testing/udev/readme-udev-arch.txt new file mode 100644 index 0000000..ac4a693 --- /dev/null +++ b/abs/core-testing/udev/readme-udev-arch.txt @@ -0,0 +1,264 @@ +========================== +Cold/Hotplugging with Udev +========================== +Version 1.1.5 +written by Tobias Powalowski <tpowa@archlinux.org> + +--------------- +* Requirements: +--------------- +- recommended kernel >=2.6.18 for this udev to work properly. +- No more DevFS device paths! If you have them, update /etc/fstab: + /dev/discs/... etc. has been deprecated in favor of the old style: + /dev/discs/disc0/part1 -> /dev/hda1 + /dev/discs/disc1/part2 -> /dev/hdb2 +- /etc/modprobe.conf should be cleaned from old install entries (see below). + +--------------- +* Udev Changes: +--------------- +- The syntax of udev rules has been changed in >=098 release, please update your rules. + --- Snip Changelog Udev 098 + Renaming of some key names: + BUS -> SUBSYSTEMS + ID -> KERNELS + SYSFS -> ATTRS + DRIVER -> DRIVERS + ATTR{file}="value" can be used now, to write to a sysfs file of the + event device. Instead of: + ..., SYSFS{type}=="0|7|14", RUN+="/bin/sh -c 'echo 60 > /sys$$DEVPATH/timeout'" + we now can do: + ..., ATTR{type}=="0|7|14", ATTR{timeout}="60" + All the PHYSDEV* keys are deprecated and will be removed from a + future kernel: + PHYDEVPATH - is the path of a parent device and should not be + needed at all. + PHYSDEVBUS - is just a SUBSYSTEM value of a parent, and can be + matched with SUBSYSTEMS== + PHYSDEVDRIVER - for bus devices it is available as ENV{DRIVER}. + Newer kernels will have DRIVER in the environment, + for older kernels udev puts in. Class device will + no longer carry this property of a parent and + DRIVERS== can be used to match such a parent value. + Note that ENV{DRIVER} is only available for a few bus devices, where + the driver is already bound at device event time. On coldplug, the + events for a lot devices are already bound to a driver, and they will have + that value set. But on hotplug, at the time the kernel creates the device, + it can't know what driver may claim the device after that, therefore + in most cases it will be empty. + --- snap Changelog Udev 098 +- optional udev >= 099 Persistent rules generator for network and cd/dvd devices was added. + +--------------- +* How it works: +--------------- +- Udev replaces the functionality of hotplug and hwdetect scripts. +- Udev does autoloading of modules and coldplugging. +- Udev loads the modules simultaneously, which is much faster, + but can cause some troubles with multiple network/sound/etc devices + (see below). +- To reload your rules please use /etc/start_udev. + +====================== +* Autoloading modules: +====================== + +------------------------------------------------------------------------- +* Module autoloading is controlled by MOD_AUTOLOAD="" in /etc/rc.conf +------------------------------------------------------------------------- +MOD_AUTOLOAD="yes" in /etc/rc.conf is necessary: +- if you want module autodetection +- if you want modules be loaded by udev (hotplugging and coldplugging) + +MOD_AUTOLOAD="no" is necessary: +- if you want to load modules strictly using 'modprobe <module>' +- if you want to load only the modules listed in the MODULES=() array + in /etc/rc.conf + +--------------- +* Blacklisting: +--------------- +- means udev will never try to load the module, even if MOD_AUTOLOAD="yes" + is set. + +You can do this in 2 ways: +- MOD_BLACKLIST=(moduleA moduleB) +- MODULES=(!moduleA !moduleB) + +Both entries mean the same thing to udev. MOD_BLACKLIST was used by hwdetect. +hwdetect does not understand the MODULES= syntax, but it doesn't have to -- it +is only used in mkinitrd now. + +================================== +* Boot parameter: load_modules=off +================================== + +- No modules are loaded during boot using udev autoloading or the MODULES array +- Useful for repairing your system if something goes wrong during udev startup + and/or during loading modules + +================================== +* Boot parameter: disablemodules= +================================== + +- list modules there that shouldn't be loaded by udev +- Syntax: disablemodules=module1,module2,module3,... +- Useful for repairing your system if something goes wrong during udev startup + and/or during loading modules and you know the module that causes the trouble. + +======================================== +* Persistent CD/DVD symlinks (optional): +======================================== + +- To enable this feature copy in /etc/udev/rules.d + 75-cd-aliases-generator.rules.optinal + to 75-cd-aliases-generator.rules + Also disable this part in /etc/udev/rules.d/40-arch.rules by putting a # in front: + --- snip + ACTION=="add", SUBSYSTEMS=="ide", KERNEL=="hd[a-z]", ATTR{removable}=="1", ATTRS{media}=="cdrom*", RUN+="/lib/udev/cdsymlinks.sh" + ACTION=="add", SUBSYSTEMS=="scsi", KERNEL=="sr[0-9]*", ATTRS{type}=="5", RUN+="/lib/udev/cdsymlinks.sh" + ACTION=="add", SUBSYSTEMS=="scsi", KERNEL=="sg[0-9]*", ATTRS{type}=="5", RUN+="/lib/udev/cdsymlinks.sh" + ACTION=="remove", SUBSYSTEMS=="block", KERNEL=="hd[a-z]", RUN+="/lib/udev/cdsymlinks.sh" + ACTION=="remove", SUBSYSTEMS=="block", KERNEL=="sr[0-9]*", RUN+="/lib/udev/cdsymlinks.sh" + ACTION=="remove", SUBSYSTEMS=="block", KERNEL=="sg[0-9]*", RUN+="/lib/udev/cdsymlinks.sh" +--- snap + +- To get the same device name for CD/DVD symlinks each time you boot, + a rule will be generated during bootup or by executing /etc/start_udev. +- Examples: dvd, cdrom ,cdrw etc. +- If you want to change those links, + modify '/etc/udev/rules.d/70-peristent-cd.rules' to your needs. + +Known issues: +The symlink name is then bound to the hardware pci adress, +if you change your CD/DVD device, you have to check the +/etc/udev/rules.d/70-peristent-net.rules file for correctness. + +====================================== +* Persistent Network names (optional): +====================================== + +- To enable this feature copy in /etc/udev/rules.d + 75-persistent-net-generator.rules.optional + to 75-persistent-net-generator.rules +- To get the same network device name each time you boot, + a rule will be generated during bootup or by executing /etc/start_udev. +- Examples: eth0, eth1, wlan0 etc. +- If you want to change those names, + modify '/etc/udev/rules.d/70-peristent-net.rules' to your needs. +- NAME= determines the name of your network card. Use these names in your + network configuration in rc.conf as well. + +Known issues: +The interface name is then bound to the hardware mac adress, +if you change your network card, you have to check the +/etc/udev/rules.d/70-peristent-net.rules file for correctness. + +==================================== +* Known Problems Hardware: +==================================== + +- BusLogic devices are broken and will cause a freeze during startup +Solution: +This is a kernel bug and no fix has been provided yet. + +- PCMCIA Card readers are not treated as removabel devices. +Solution: +To get access to them with hal's pmount backend add them to /etc/pmount.allow + +==================================== +* Known Problems MOD_AUTOLOAD="yes": +==================================== + +----------------------------------------------------------------------------- +* Sound is not working or modules (eg. parport) are not loaded automatically: +----------------------------------------------------------------------------- +Solution: +- Do you have a clean /etc/modprobe.conf? + - A clean /etc/modprobe.conf is empty. The stock modprobe.conf file + contains nothing +- alsaconf can write output to modprobe.conf. Please keep that in mind. + +--------------------------------------------- +* Devices get mixed up eg. Network/Soundcards +--------------------------------------------- +- Because udev loads all the modules at once, sometimes devices are initialized + in different orders (eg. network cards switch eth0 and eth1, sound cards + the same) + +Solution: +- Load them in MODULES=() array in the order you need them +- eg: MODULES=(moduleA moduleB) + +Second solution for network: +- The "proper" way to configure net interfaces to hold static names within + udev rules. Add lines like these to a custom rules file such as + /etc/udev/rules.d/01-network.rules: + SUBSYSTEM=="net", SYSFS{address}=="aa:bb:cc:dd:ee:ff", NAME="lan0" + SUBSYSTEM=="net", SYSFS{address}=="ff:ee:dd:cc:bb:aa", NAME="wlan0" + +- To get the right mac address use this command: + udevinfo -a -p /sys/class/net/<yourdevice> +- Make sure you use lower-case hex values in your udev rules. +- NAME= determines the name of your network card. Use these names in your + network configuration in rc.conf as well. + +Third solution for network: +- check Persistent Network part + +----------------------------------- +* Network 8139too & 8139cp problem: +----------------------------------- +- Both modules have the same kernel entry, which can cause problems. +Solution: +- Enter the one you need in MODULES=() and blacklist the other one +- eg: MODULES=(!8139cp 8139too) +- The example tells udev to ignore 8139cp module and load 8139too afterwards. + +-------------------------------------------------------- +* You need a special loading order to get devices going: +-------------------------------------------------------- +- Kernel loads modules in wrong order. +Solution: +- Load them in the correct order in MODULES=() + +----------------------------- +* Module is not autodetected: +----------------------------- +- If your device does not provide a modalias in /sys it cannot be autodetected. +- If modalias is not combined to a kernel module it cannot be autodetected. +Known modules that are not autodetected: +- SCSI CONTROLLER: + scsi_transport_sas ultrastor qlogicfas eata BusLogic pas16 wd7000 sym53c416 + g_NCR5380_mmio fdomain u14-34f dtc initio in2000 imm t128 aha1542 aha152x + atp870u g_NCR5380 NCR53c406a qlogicfas408 megaraid_mm advansys +- NETWORK CARDS: + hp ne de4x5 wd cs89x0 eepro smc9194 seeq8005 ni52 ni65 ac3200 smc-ultra + at1700 hp-plus depca eexpress 82596 de600 eth16i de620 lance ewrk3 e2100 + lp486e 3c501 3c503 3c505 3c507 3c509 3c515 myri10ge +Solution: +- Enter the one you need in MODULES=() + +======================================= +* Known Problems with MOD_AUTOLOAD="no" +======================================= + +----------------------------------------------------------------- +* Modules are not loaded anymore during coldplug or hotplug event +----------------------------------------------------------------- +- Udev is usually responsible for this, but the MOD_AUTOLOAD switch will + now disable it. If you want automatic hot/cold-plugging, turn on + MOD_AUTOLOAD. Otherwise you will have to load all your modules manually, + either with /sbin/modprobe or entries in the MODULES=() array. +Solution: +- For bootup (coldplug) enter this in rc.conf: MODULES=(moduleA moduleB) +- After bootup (hotplug) use this: modprobe <moduleA> + +========================================= +* Known problems for custom kernel users: +========================================= + +---------------------------- +* Udev doesn't start at all: +---------------------------- +- Check Requirements list |