Features/DeviceKit

DeviceKit

Summary

DeviceKit is a simple system service that a) can enumerate devices; b) emits signals when devices are added removed; c) provides a way to merge device information / quirks onto devices. It is designed to partially replace hal and overcome some of the design limitiations of hal.

Apart from DeviceKit itself, there is DeviceKit-disks, which is a system service to keep track of block devices, and palimpsest, which is a graphical frontend for DeviceKit-disks. There is also a DeviceKit-power, which will take over the power management-related parts of hal.

Furthermore, there will be a nautilus extension to format disks.

Owner

• Name: DavidZeuthen

Current status

• Targeted release: Fedora 10
• Last updated: 2008-07-10
• Percentage of completion: 50%

DeviceKit is still not in rawhide, since there are still some device-mapper prerequisites missing. The current goal is to have it in rawhide by F10 alpha.

Detailed Description

David has written an extensive explanation of the DeviceKit architecture, and the motivation for rewriting hal. Read all about it here

There is a dedicated devkit-devel mailing list now.

Benefit to Fedora

Fedora gains a comprehensive graphical disk management tool which provides functionality that so far was almost exclusively available in the partitioning screen of anaconda. The tools integrate nicely into the desktop (by e.g. providing a "Format disk..." menuitem in the nautilus context menu where appropriate).

Scope

DeviceKit depends on bug fixes and enhancements in unreleased versions of a number of components, such as kernel, udev, mdadm, lvm. These will have to appear in rawhide first. Also, in order to peacefully coexist with DeviceKit-disks, hal will need to undergo disk-ectomy. Components which depend directly on the disk functionality in hal, such as gvfs, Solid and thunar-volman, have to be ported to DeviceKit-disks.

For completeness, here is a list of all packages in Fedora that depend on hal, libhal.so.1 or libhal-storage.so.1.

• anaconda - will be ported when and if the installer team thinks that is a good idea
• bluez-gnome - only uses libhal to get the formfactor
• brasero - uses libhal to interact with drives
• cheese - uses libhal to find webcams
• concordance - only requires hal to install fdi files, should be fine
• conexusmm - uses libhal to find serial ports
• control-center - uses libhal to find sound devices
• emelfm2 - uses libhal to find storage devices
• evolution - ipod plugin uses libhal to find ipod devices
• exo - uses libhal to find storage devices
• gdm - should be fine
• gimp - uses libhal to find input devices
• gnomad2 - uses libhal to find portable audio players
• gnome-device-manager - needs porting
• gnome-keyring - uses libhal to monitor removable storage devices
• gnome-mount - needs porting
• gnome-pilot - uses libhal to find usb devices
• gnome-power-manager - needs porting to DeviceKit-power
• gnome-utils - uses libhal to find floppy device
• gnome-vfs2 - needs porting
• gnome-volume-manager - uses libhal to handle volumes
• gparted - only requires hal to install fdi files, should be fine
• gstreamer-plugins-good - uses libhal to find audio devices
• gtkpod - uses libhal to find storage devices
• gvfs - needs porting
• gxine - uses libhal to find block devices
• hal-cups-utils - uses libhal to find printers
• halevt - needs porting
• hplip - requires hal to install fdi files, should be fine
• k3b - uses libhal to find cdrom devices
• kdebase3
• knetworkmanager
• kpowersave - should be ported to DeviceKit-power
• libipoddevice - uses libhal to find ipod devices
• libmtp - requires hal to install fdi files, should be fine
• libsynce - uses libhal to find pda devices
• nautilus-cd-burner - uses hal to interact with drives
• NetworkManager - uses libhal to find network devices
• nut - needs porting to DeviceKit-power
• odccm - uses libhal to find pda devices
• oxine - uses libhal to monitor volumes and drives
• pcmanfm - uses libhal to find volumes and drives
• pmount - uses hal to mount and unmount devices
• pm-utils - requires hal to install fdi files, should be fine
• pulseaudio - uses libhal to find audio devices
• python-minihallib - python wrapper around hal api
• rhpxl - uses hal to find mice and video cards
• rhythmbox - uses libhal to find remote audio players
• sane-backends - only requires hal to install an fdi file, should be fine
• synaptics - only requires hal to install an fdi file, should be fine
• synce-hal
• thinkfinger - requires hal to install some fdi files, should be fine
• Thunar - uses libhal to monitor volumes and drives
• thunar-volman - uses libhal to monitor removable devices
• totem-pl-parser - uses libhal to find audio cds
• tracker - only uses libhal to track ac/battery status, should be ported to DK-power
• xfce4-volstatus-icon - uses libhal to monitor volumes and drives
• xorg-x11-server - uses libhal to find keyboards

Test Plan

1. Use palimpsest (the graphical frontend) to create, modify and delete partitions and file systems on various media, such as usb sticks, cds, removable hard disks, etc.
2. Use palimpsest to encrypt partitions and to change passwords for existing encrypted partitions.
3. Verify that palimpsest correctly reports smart data from disks which support it.
4. Test the raid support
5. Test the lvm support
6. Test that desktop applications like nautilus and the gedit (file chooser) see volumes and mounts
7. Similar for other desktop environments, if they are ported to DeviceKit

User Experience

There is a new menu item that brings up gnome-disc-utility.

The nautilus context menu offers to format discs/usb sticks and other devices.

gnome-disc-utility is a graphical interface for all disc-related tasks, from partitioning and file system creation to encryption, raid and lvm.

Dependencies

hal needs to be built without disc support.

gvfs needs to be built against DeviceKit-disks, and the volume monitor in gvfs must be moved out of process to make it a singleton.

Solid's (KDE's) disk management also needs to be ported to DeviceKit-disks.

Contingency Plan

Don't add the new packages to F10, undo the hal-disk-ectomy, rebuild gvfs against hal instead of DeviceKit-disks.

Documentation

API docs are here: http://hal.freedesktop.org/docs/DeviceKit/

Release Notes

Should not be necessary.

It might be a good idea to mention the encryption support where the release notes talk about encryption.

Comments and Discussion

See Talk:Features/DeviceKit

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