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 with the upstream implementation and 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 these reduce power consumption and thus improve battery lifetime.

• resolvconf is now used to manage /etc/resolv.conf on all Ubuntu systems. You can learn more here

• Backports are now more easily accessible -- to enable users to more easily receive new versions of software, the Ubuntu Backports repository is now enabled by default. Packages from backports will not be installed by default — they must explicitly be selected in package management software. However, once installed, packages from backports will automatically be upgraded to newer versions.
• DVD Images -- the DVD images have been cleaned up significantly reducing their size to around 1.5GB to ease consumption. The remaining software remains available via download.

Linux v3.2.14 Kernel

Ubuntu 12.04 LTS ships with an updated kernel moving from the mainline v3.0 series to the mainline v3.2 series. At release we are shipping with the Ubuntu 3.2.0-23.36 kernel which is based on the v3.2.14 upstream stable Linux kernel. The mainline v3.0 to v3.2 stable series update brings a number of new features. Some highlights include:

• ext4 gains support for larger base block sizes
• btrfs has more work addressing data integrity issues
• device mapper gains thin provisioning and recursive snapshots
• more work to improve performance under high writeback load
• networking improvements for congested networks
• ext3 moves to using filesystem barriers
• memory allocator improvements
• VFS scalability improvements
• a new iSCSI implementation
• software wait gains bad block management

Key changes in the Ubuntu kernel since the 3.0.0-12.20 Ubuntu kernel as 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.

• Support for a new armhf kernel flavor has been introduced.

• The non-smp PowerPC kernel flavor has been removed. All hardware currently supported by the non-smp PowerPC kernel flavor should also be supported by the smp PowerPC kernel flavor.

• 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 has 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 and 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 has 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. More details are available in the Upstart Technical Overview.

GNU Toolchain

Ubuntu 12.04 is distributed with a default toolchain that includes: GCC 4.6.3 (and changes from Linaro GCC 4.6-2012.02), binutils 2.22, eglibc 2.15, and Linaro gdb 7.4-2012.04.

Compared to the 11.10 release the toolchain did see only incremental changes and bug fixes; comparing to the 10.04 LTS release, GCC updates include

• Updated frontends for better standards support (Ada 2012, Objective-C 2.0, improved experimental support for the upcoming C++0x ISO C++ standard, Fortran 2003 and 2008 improvements, new Go frontend)
• Improved optimizations, including better inter-procedural optimizations, and link time optimization (LTO).

Further information can be found upstream (GCC-4.6, GCC-4.5, binutils, gas, ld, gdb).

Python Toolchain

• Ubuntu 12.04 includes Python 2.7.3 and Python 3.2.3 Python 2.6 is no longer available for install.

• There is expanded support for Python 3 in this release, with Python 3 ports of python-dbus, python-feedparser, germinate, lazr.ui, wadllib, python-defer, python-keyring, and python-qt4 now included, among others.

Java Toolchain

The default run time for Java is OpenJDK 6b24 (IcedTea 1.11.1). OpenJDK 7u3 (IcedTea 2.1) is available in the archive as well.

Boot, Installation and Post-Installation

• [Dell Studio XPS 1340,Alienware m17x] Kernel panic and hang on boot due to the ite-cir driver. A patch has been sent upstream and a test kernel is referenced in the bug report. The fix will be immediately available as a kernel update from the precise-updates pocket following 12.04's release. (984387)

• When closing the lid on a Unibody Macbook, the screen interacts with the touchpad. This can cause spurious gestures and clicks, and potentially lead to corrupted input driver state if the laptop suspends. To work around the issue, remove and reload the kernel module after resume by running:

  $ sudo rmmod bcm5974
  $ sudo modprobe bcm5974

  Note that this may disable some touchpad options, for example horizontal scrolling. These options can be re-enabled by visiting the Mouse and Touchpad settings. This is planned to be fixed in a post-release update (968845).

• Importing of existing Windows user accounts fails in some cases. (987902)

• Wubi (the Ubuntu installer for Windows) is not available as an option on the Ubuntu Desktop/DVD any more. Instead, it is now a separate download.

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 on 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)

• In some cases update-manager might appear to hang indefinitely. In that case, open the expander at the bottom and check if there is a debconf question which needs to be answered. (979661)

• Upgrades from Ubuntu 10.04 LTS to 12.04 LTS do not work using the alternate CD or the server CD as a package repository. It is recommended that users running Ubuntu 10.04 LTS wait for the 12.04.1 LTS point release, scheduled for July, before upgrading. (988941)

• If you are running a KVM host with libvirt and are upgrading from Ubuntu 10.04 LTS to 12.04 LTS you may find that some existing virtual machines are no longer recognized (virsh list --all). A change to each guest's XML file may be in order that is related to how console and serial devices are now configured. (931350)

Kernel

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

• [Dell Studio XPS 1340,Alienware m17x] Kernel panic and hang on boot due to the ite-cir driver. A patch has been sent upstream and a test kernel is referenced in the bug report. The fix will be immediately available as a kernel update from the precise-updates pocket following 12.04's release. (984387)

• Missing support for Sentelic touchpad in Asus K53U notebook. Patches have been backported and will be immediately available as a kernel update from the precise-updates pocket following 12.04's release. (969334)

• Missing support for BCM20702A0 Broadcom bluetooth device [0489:e042]. A patch has been sent upstream. The fix will be immediately available as a kernel update from the precise-updates pocket following 12.04's release. (980965)

• Buffer overflows in comedi driver. Patches have been backported from upstream and a test kernel is referenced in the bug report. The fix will be immediately available as a kernel update from the precise-updates pocket following 12.04's release. (981234)

• Intel gma 4500mhd external monitor suffers from a scrambled picture. A patches has been backported from upstream. The fix will be immediately available as a kernel update from the precise-updates pocket following 12.04's release. (796030)

• Kernel Oops - BUG: unable to handle kernel paging request; RIP: nfs_have_delegation+0x9/0x40 [nfs]. Some users attempting to run NFS clients on 12.04 appear to be affected. A test kernel is referenced from the bug report. Patches have been backported from upstream and will be immediately available in a kernel update from the precise-updates pocket following 12.04's release. (974664)

• Patches from upstream stable v3.2.15 and v3.2.16 will undergo a baking period in the precise-proposed pocket during the first kernel SRU cycle. They will then be released as a kernel update from the precise-updates pocket approximately 3 weeks after 12.04 releases. (981162, 987337)

• hid-logitech-dj driver missing from the installer. It has been added to the d-i input-modules udeb and will be included in the 12.04.1 point release. (975198)

• rtl8187 driver missing from the installer. It has been added to the d-i nic-usb-modules udeb and will be included in the 12.04.1 point release. (971719)

• eGalaxis Touchscreen Driver does not work. Patches have been backported from upstream and will be immediately available in a kernel update from the precise-updates pocket following 12.04's release. (913164)

• ATI/radeon framebuffers on PowerPC only enabled as modules and not built in. This results in issues such as booting to a command prompt, loss of tty consoles, and loss of suspend. A patch to build these in have been applied and will be immediately available in a kernel update from the precise-updates pocket following 12.04's release. (949288)

• On systems with an ATI Radeon 9200 graphics card the system will boot to a black screen. As a work around edit the kernel command line in the boot loader and add "nomodeset". (725580)

• Fujitsu Siemens Amilo M 7400 and Maxdata 7000DX wireless RF kill handling triggers a kernel panic preventing wireless from operating correctly. This may be worked around by editing your kernel command line and adding "noexec=off". (979253)

• Beagle XM systems which are capable of running at 1GHZ will be initialised at 800MHZ leading to slower than optimal performance. (771537)

• Some EFI systems fail to boot in EFI mode, BIOS mode is advised in these situations. (721576)