New Features

Common Infrastructure

• Up until Ubuntu 11.10, administrator access using the sudo tool was granted via the "admin" Unix group. In Ubuntu 12.04, administrator access will be granted via the "sudo" group. This makes Ubuntu more consistent the upstream implementation and with Debian. For compatibility purposes, the "admin" group will continue to provide sudo/administrator access in 12.04.

• Hibernate (suspend to disk) has been disabled by default, as it was found to be unreliable, very slow and confusing to have two suspend modes. See bug 812394 for details. If you want to re-enable it, please follow this recipe.

• pm-utils now has two new scripts to power down USB and various PCI devices in battery mode. A number of desktop packages were fixed to wake up less often. Both of this reduces power consumption and thus improves battery lifetime.
• DNS resolution is now done through dnsmasq, which should help split-DNS VPNs and faster DNS resolution.

• resolvconf is now used to manage /etc/resolv.conf on all Ubuntu systems. For systems using Network Manager DNS resolution is now done through dnsmasq, which should help split-DNS VPNs and faster DNS resolution. You can learn more here

Linux v3.2.14 Kernel

Ubuntu 12.04 ships with the 3.2.0-23.36 Ubuntu kernel which is based on the v3.2.14 upstream stable Linux kernel. Key changes since the 3.0.0-12.20 Ubuntu kernel shipped in the 11.10 Ubuntu release include:

• Rebase to upstream stable Linux kernel v3.2.14.

• The amd64 -generic and -server kernel flavors have been merged into a single -generic kernel flavor for Ubuntu 12.04. Given the few differences that existed between the two flavors, it only made sense to merge the two and reduce the overall maintenance burden over the life of this LTS release.

• The non-smp PowerPC kernel flavor has been removed.

• RC6 is enabled by default for Sandy Bridge systems. RC6 is a technology which allows the GPU to go into a very low power consumption state when the GPU is idle (down to 0W). It results in considerable power savings when this stage is activated. When comparing under idle loads with machine state where RC6 is disabled, improved power usage of around 40-60% has been witnessed.

• An improved set of jack detection patches have been backported from the upstream v3.3 Linux kernel.

• An updated AppArmor patch set has been included to better align with what is landing upstream.

• Applied an enabled the seccomp filters feature which uses the packet filtering machinery (BPF) to restrict access to system calls.

• A set of kexec fixes for arm from v3.3-rc1 have also been backported.

• We've also conducted an extensive review of Ubuntu kernel configs and made numerous config changes as a result.

Upstart 1.5

Upstart has been updated to version 1.5. For full details, see PrecisePangolin/ReleaseNotes/TechnicalOverviewUpstart.

Known Issues

Boot, Installation and Post-Installation

Upgrades

• Aptitude does not work on 64 bit systems without disabling multiarch in /etc/dpkg/dpkg.cfg.d/multiarch . (831768)

• If you have i386 packages installed an an amd64 system in Ubuntu 11.10, it is strongly recommended that you install the versions of apt and dpkg from oneiric-updates before upgrading. A number of multiarch-affecting upgrade issues have been fixed in those versions. (850264, 902603)

Kernel

• On ARM omap images, the networking support for the Beagle XM board is broken (838200)