What is the linux-image-extra package for and do I need it?
Emily Wong
I occasionally update my kernel from this web site
I have been always downloading 3 deb files for installing linux header all, linux image and linux headers. I noticed one more deb file recently for 64 bit kernel called Linux-image-extra.
I would like to know what does kernel file Linux-image-extra do and should I also install it?
02 Answers
This answer is obsolete for modern Ubuntu releases
Without the extra package, most hardware won't work!
It contains extra drivers left out of the base kernel package; install it only if you need these drivers
Sometimes, a specific variant of the linux-image is slimmed down by removing the less common kernel modules (drivers). In this case, the linux-image-extra package simply contains all of the "extra" kernel modules which were left out.
Officially, this only happens for the
-virtualimage; the most common hypervisors (Virtualbox, VMWare, Xen, KVM) emulate a well-defined and restricted set of hardware, so removing unnecessary drivers which increase the size of the kernel/initrd is a good idea. You can always get them back by installing the extras package.The kernel team also appears to have adopted this method for some of the mainline-PPA
-generickernels; the reasoning and solution remain the same -- if it looks like the base kernel image is missing a module you need, install extras.As far as I know, the above approach has not been taken for the Quantal kernels -- only -virtual is affected as usual.
In previous Ubuntu versions, the linux-image-extras was optional, tailored for virtual machines / servers.
As of Ubuntu 14.04, linux-image is a slim package (for virtual machines), and linux-image-extras now contains many drivers required for desktops.
In particular, usb-hid (keyboard support), is only present once you install the linux-image-extras package. A common mishap, which results in TTY1 hanging on boot, and unable to login using a keyboard.
Mainline kernels are shipped using a single linux-image package, such as linux-image-3.19.0-031900rc1-generic_3.19.0-031900rc1.201412210135_amd64.deb