While looking into how to look up Debian packages based on hardware
-information, to find the packages that support a given piece of
-hardware, I refreshed my memory regarding modalias values, and decided
-to document the details. Here are my findings so far, also available
-in
-the
-Debian Edu subversion repository:
-
-
Modalias decoded
-
-
This document try to explain what the different types of modalias
-values stands for. It is in part based on information from
-<URL: https://wiki.archlinux.org/index.php/Modalias >,
-<URL: http://unix.stackexchange.com/questions/26132/how-to-assign-usb-driver-to-device >,
-<URL: http://code.metager.de/source/history/linux/stable/scripts/mod/file2alias.c > and
-<URL: http://cvs.savannah.gnu.org/viewvc/dmidecode/dmidecode.c?root=dmidecode&view=markup >.
-
-
The modalias entries for a given Linux machine can be found using
-this shell script:
-
-
-find /sys -name modalias -print0 | xargs -0 cat | sort -u
-
-
-
The supported modalias globs for a given kernel module can be found
-using modinfo:
-
-
-% /sbin/modinfo psmouse | grep alias:
-alias: serio:ty05pr*id*ex*
-alias: serio:ty01pr*id*ex*
-%
-
-
-
PCI subtype
-
-
A typical PCI entry can look like this. This is an Intel Host
-Bridge memory controller:
-
-
-pci:v00008086d00002770sv00001028sd000001ADbc06sc00i00
-
-
-
This represent these values:
-
-
- v 00008086 (vendor)
- d 00002770 (device)
- sv 00001028 (subvendor)
- sd 000001AD (subdevice)
- bc 06 (bus class)
- sc 00 (bus subclass)
- i 00 (interface)
-
-
-
The vendor/device values are the same values outputted from 'lspci
--n' as 8086:2770. The bus class/subclass is also shown by lspci as
-0600. The 0600 class is a host bridge. Other useful bus values are
-0300 (VGA compatible card) and 0200 (Ethernet controller).
-
-
Not sure how to figure out the interface value, nor what it
-means.
-
-
USB subtype
-
-
Some typical USB entries can look like this. This is an internal
-USB hub in a laptop:
-
-
-usb:v1D6Bp0001d0206dc09dsc00dp00ic09isc00ip00
-
-
-
Here is the values included in this alias:
-
-
- v 1D6B (device vendor)
- p 0001 (device product)
- d 0206 (bcddevice)
- dc 09 (device class)
- dsc 00 (device subclass)
- dp 00 (device protocol)
- ic 09 (interface class)
- isc 00 (interface subclass)
- ip 00 (interface protocol)
-
-
-
The 0900 device class/subclass means hub. Some times the relevant
-class is in the interface class section. For a simple USB web camera,
-these alias entries show up:
-
-
-usb:v0AC8p3420d5000dcEFdsc02dp01ic01isc01ip00
-
usb:v0AC8p3420d5000dcEFdsc02dp01ic01isc02ip00
-
usb:v0AC8p3420d5000dcEFdsc02dp01ic0Eisc01ip00
-
usb:v0AC8p3420d5000dcEFdsc02dp01ic0Eisc02ip00
-
-
-
Interface class 0E01 is video control, 0E02 is video streaming (aka
-camera), 0101 is audio control device and 0102 is audio streaming (aka
-microphone). Thus this is a camera with microphone included.
-
-
ACPI subtype
-
-
The ACPI type is used for several non-PCI/USB stuff. This is an IR
-receiver in a Thinkpad X40:
-
-
-acpi:IBM0071:PNP0511:
-
-
-
The values between the colons are IDs.
-
-
DMI subtype
-
-
The DMI table contain lots of information about the computer case
-and model. This is an entry for a IBM Thinkpad X40, fetched from
-/sys/devices/virtual/dmi/id/modalias:
-
-
-dmi:bvnIBM:bvr1UETB6WW(1.66):bd06/15/2005:svnIBM:pn2371H4G:pvrThinkPadX40:rvnIBM:rn2371H4G:rvrNotAvailable:cvnIBM:ct10:cvrNotAvailable:
-
-
-
The values present are
-
-
- bvn IBM (BIOS vendor)
- bvr 1UETB6WW(1.66) (BIOS version)
- bd 06/15/2005 (BIOS date)
- svn IBM (system vendor)
- pn 2371H4G (product name)
- pvr ThinkPadX40 (product version)
- rvn IBM (board vendor)
- rn 2371H4G (board name)
- rvr NotAvailable (board version)
- cvn IBM (chassis vendor)
- ct 10 (chassis type)
- cvr NotAvailable (chassis version)
-
-
-
The chassis type 10 is Notebook. Other interesting values can be
-found in the dmidecode source:
-
-
- 3 Desktop
- 4 Low Profile Desktop
- 5 Pizza Box
- 6 Mini Tower
- 7 Tower
- 8 Portable
- 9 Laptop
- 10 Notebook
- 11 Hand Held
- 12 Docking Station
- 13 All In One
- 14 Sub Notebook
- 15 Space-saving
- 16 Lunch Box
- 17 Main Server Chassis
- 18 Expansion Chassis
- 19 Sub Chassis
- 20 Bus Expansion Chassis
- 21 Peripheral Chassis
- 22 RAID Chassis
- 23 Rack Mount Chassis
- 24 Sealed-case PC
- 25 Multi-system
- 26 CompactPCI
- 27 AdvancedTCA
- 28 Blade
- 29 Blade Enclosing
-
-
-
The chassis type values are not always accurately set in the DMI
-table. For example my home server is a tower, but the DMI modalias
-claim it is a desktop.
-
-
SerIO subtype
-
-
This type is used for PS/2 mouse plugs. One example is from my
-test machine:
-
-
-serio:ty01pr00id00ex00
-
-
-
The values present are
-
-
- ty 01 (type)
- pr 00 (prototype)
- id 00 (id)
- ex 00 (extra)
-
-
-
This type is supported by the psmouse driver. I am not sure what
-the valid values are.
-
-
Other subtypes
-
-
There are heaps of other modalias subtypes according to
-file2alias.c. There is the rest of the list from that source: amba,
-ap, bcma, ccw, css, eisa, hid, i2c, ieee1394, input, ipack, isapnp,
-mdio, of, parisc, pcmcia, platform, scsi, sdio, spi, ssb, vio, virtio,
-vmbus, x86cpu and zorro. I did not spend time documenting all of
-these, as they do not seem relevant for my intended use with mapping
-hardware to packages when new stuff is inserted during run time.
-
-
Looking up kernel modules using modalias values
-
-
To check which kernel modules provide support for a given modalias,
-one can use the following shell script:
-
-
- for id in $(find /sys -name modalias -print0 | xargs -0 cat | sort -u); do \
- echo "$id" ; \
- /sbin/modprobe --show-depends "$id"|sed 's/^/ /' ; \
- done
-
-
-
The output can look like this (only the first few entries as the
-list is very long on my test machine):
-
-
- acpi:ACPI0003:
- insmod /lib/modules/2.6.32-5-686/kernel/drivers/acpi/ac.ko
- acpi:device:
- FATAL: Module acpi:device: not found.
- acpi:IBM0068:
- insmod /lib/modules/2.6.32-5-686/kernel/drivers/char/nvram.ko
- insmod /lib/modules/2.6.32-5-686/kernel/drivers/leds/led-class.ko
- insmod /lib/modules/2.6.32-5-686/kernel/net/rfkill/rfkill.ko
- insmod /lib/modules/2.6.32-5-686/kernel/drivers/platform/x86/thinkpad_acpi.ko
- acpi:IBM0071:PNP0511:
- insmod /lib/modules/2.6.32-5-686/kernel/lib/crc-ccitt.ko
- insmod /lib/modules/2.6.32-5-686/kernel/net/irda/irda.ko
- insmod /lib/modules/2.6.32-5-686/kernel/drivers/net/irda/nsc-ircc.ko
- [...]
-
-
-
If you want to help implementing a system to let us propose what
-packages to install when new hardware is plugged into a Debian
-machine, please send me an email or talk to me on
-#debian-devel.
-
-
Update 2013-01-15: Rewrite "cat $(find ...)" to
-"find ... -print0 | xargs -0 cat" to make sure it handle directories
-in /sys/ with space in them.
-
