Estas notas de publicación documentan problemas conocidos con Ubuntu 9.04 y sus variantes.

Requisitos del sistema

La cantidad mínima de memoria necesaria para Ubuntu 9.04 es 256 MiB de RAM. (Tenga en cuenta que su tarjeta gráfica puede usar parte de la memoria de su sistema, y que por tanto no toda estaría disponible.)

Cuando sólo se dispone de la cantidad mínima de memoria, el proceso de instalación tarda más de lo normal, pero se completa satisfactoriamente y el sistema funciona de forma adecuada una vez instalado. Los sistemas con poca memoria podrán usar el desktop CD para instalar Ubuntu 8.10 seleccionando «Instalar Ubuntu» en el menú de arranque para ejecutar únicamente el instalador, en lugar de iniciar el escritorio completo seleccionando «Probar Ubuntu sin alterar su equipo».

Instalación

Los paquetes recomendados se instalan de forma predeterminada

En concordancia con el Manual de directivas de Debian (que dice «El campo 'Recommends' debe enumerar los paquetes que deberían ir junto con este en todas las instalaciones menos en las poco usuales»), el sistema de gestión de paquetes ahora instala de forma predeterminada los paquetes que se enumeran en el campo Recommends: de otros paquetes instalados, además de los indicados en Depends:. Si desea evitar este comportamiento con paquetes específicos, use apt-get --no-install-recommends; si desea hacerlo permanente, establezca APT::Install-Recommends "false"; en /etc/apt/apt.conf. Tenga en cuenta que esto puede provocar pérdida de características en algunos programas.

(Este cambio se llevó a cabo en Ubuntu 8.10.)

Actualización

Los usuarios de Kubuntu pueden actualizar directamente de Kubuntu 8.04 a Kubuntu 9.04. A los usuarios que actualicen de esta forma se les aconseja que lean las notas de publicación de Ubuntu 8.10, ya que los problemas allí descritos también se aplican en este caso.

Boot failures on systems with Intel D945 motherboards

Users have reported slower than normal detection of SATA hard drives on systems with Intel D945 motherboards in Ubuntu 9.04. This may cause the system to drop to a busybox initramfs shell on boot with a "Gave up waiting for root device." error. Wait a minute or two and then exit the initramfs shell by typing 'exit'. Booting should proceed normally. If it doesn't, wait a bit longer and try again. Once the system boots, edit /boot/grub/menu.lst and add rootdelay=90 to the kernel stanza for your current kernel. (Bug 290153).

Upgrades from beta may use LABEL= in /etc/fstab

Systems installed using Jaunty Alpha 5, Jaunty Alpha 6, or the Ubuntu 9.04 beta may use LABEL= syntax in /etc/fstab to identify file systems. This may cause unexpected behaviour later if another disk (such as a USB drive) is added later containing file systems with clashing labels. Unless you are sure that this is what you intend, we recommend that you switch to using universally unique identifiers (UUIDs) instead.

For example, if a file system is identified as LABEL=home in /etc/fstab, you can find the UUID as follows:

blkid -o value -s UUID -l -t LABEL=home

You can then replace LABEL=home with UUID=output, where output is the output of blkid.

Systems installed using the release candidate or final release of Ubuntu 9.04 do not have this problem.

Upgrades from Ubuntu 8.10 may have lilo installed

Ubuntu 8.10 systems installed from the desktop CD mistakenly had the lilo package installed as well as grub, although grub was used for booting. If you use the recommended Update Manager upgrade method, then the lilo package will be removed if it does not appear to be used. If you upgrade using some other method and are sure that you only use the GRUB boot loader, then we recommend that you remove the lilo package manually. Bug 314004

Setting wireless regulatory domain via module option no longer supported

Ubuntu 9.04 enables the CRDA wireless regulatory framework for controlling which wireless channels are usable and visible in a particular location. If you previously had to use the module option similar to that below in /etc/modprobe.d/options to allow access to certain channels in your locality then you may find that wireless will not function at all:

• options cfg80211 ieee80211_regdom=EU

You should remove this kernel module option on upgrade to Ubuntu 9.04 and use the iw reg command instead.

Other known issues

Switching to ext4 requires manually updating grub

If you choose to upgrade your / or /boot filesystem in place from ext2 or ext3 to ext4 (as documented on the ext4 wiki), then you must also use the grub-install command after upgrading to Ubuntu 9.04 to reinstall your boot loader. If you do not do this, then the version of GRUB installed in your boot sector will not be able to read the kernel from the ext4 filesystem and your system will fail to boot.

Occasional hangs possible on ARM architecture

The ARM port currently does not support the ppoll() & pselect() system syscalls, which will sometimes cause a failure to mount the root filesystem on boot. This is a race condition, and retrying the boot will usually clear the problem. The work to add the syscalls is currently underway and will be delivered as an update to the Ubuntu 9.04 kernel some time after release.

Performance regressions on Intel graphics cards

Users of Intel video chipsets have reported performance regressions in Ubuntu 8.10 compared with previous releases (bug 252094). Many of the issues have been resolved in Ubuntu 9.04, but some remain.

• Some users have found improved performance by using the "greedy" migration heuristic. This can be done by running "sudo gedit /etc/X11/xorg.conf", and adding Option "MigrationHeuristic" "greedy" to the Device section of your xorg.conf.

• Alternately, a new experimental acceleration architecture option, "DRI2/UXA", is available for Intel graphics users which our testing has found provides significant performance improvements in some cases, but has also shown risk of severe stability problems. You can opt-in to enable this by running "sudo gedit /etc/X11/xorg.conf", and adding Option "AccelMethod" "UXA" to the Device section of your xorg.conf. Users wishing to maximize stability should stay with the standard default acceleration method, "EXA".

• If none of the above helps, some users reported success with using an older driver version.

Suspend/Hibernate hangs with Intel graphics cards

Users of Intel video chipsets reported that the display freezes a few minutes after resuming from suspend or hibernate (bug 339091). As a workaround you can add Option "DRI" "off" to the Device section of /etc/X11/xorg.conf, as described above. This will disable 3D acceleration and desktop effects, but makes suspend work reliably again.