Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Next revision
Previous revision
wiki:choosing_and_installing_kernels [2013/10/22 18:25] – created danboidwiki:choosing_and_installing_kernels [2013/11/18 20:46] (current) – [Are you running the best kernel for your hardware?] danboid
Line 5: Line 5:
 The kernel can be seen as the engine of the Linux OS - it contains nearly all of the drivers for your hardware. KXStudio 12.04.3 runs the 3.8.0-32-lowlatency kernel by default. This kernel will be fine for most people but, most significantly for users of an audio-centric distro, you may not be able to run JACK with optimal settings if you are using USB audio devices such as the Focusrite Scarlett family of USB devices, for example.  The kernel can be seen as the engine of the Linux OS - it contains nearly all of the drivers for your hardware. KXStudio 12.04.3 runs the 3.8.0-32-lowlatency kernel by default. This kernel will be fine for most people but, most significantly for users of an audio-centric distro, you may not be able to run JACK with optimal settings if you are using USB audio devices such as the Focusrite Scarlett family of USB devices, for example. 
  
-Both during and before Linux 3.5 as well as since kernel 3.11, JACK runs happily with a buffer size of 64 @ 3 periods/buffer, giving a low JACK latency but under the 3.8 kernels you'll likely find you cannot start JACK at a buffer size less than 1024 with some USB devices. Users of PCI, integrated and FireWire audio devices need not concern themselves with this and it also seems that not all USB audio devices have issues with 3.8 so in many cases you won't know which kernel you need until you have tested any USB audio devices you have.+Both during and before Linux 3.5 as well as since kernel 3.11, JACK runs happily with a buffer size of 64 @ 3 periods/buffer @ 48Khz on the Scarlett USB devices, giving a low JACK latency but under the 3.8 kernels you're likely to find you cannot start JACK at a buffer size less than 1024 with such USB hardware. Users of PCI, integrated and FireWire audio devices need not concern themselves with this and it also seems that not all USB audio devices have issues with 3.8 so in many cases you won't know which kernel you need until you have tested your USB audio devices.
  
-Another notable difference between the kernels currently available from the KXStudio repositories is the greatly improved performance of the open source AMD/ATI Radeon drivers within 3.11 and later kernels due to the kernel and the FLOSS radeon drivers gaining support for re-clocking the AMD GPUs so they can run at full speed. I have not personally verified this myself yet and I suspect it may also involve updating Xorg and mesa using PPA's that are not included with or supported by KXStudio+Another notable difference between the kernels currently available from the KXStudio repositories is the greatly improved performance of the open source AMD/ATI Radeon drivers within 3.11 and later kernels due to the kernel and the FLOSS Radeon drivers gaining support for re-clocking the AMD GPUs so they can run at full speed. I have not personally verified this myself yet and I suspect it may also involve updating Xorg and Mesa using PPA's that are not included with or supported by KXStudio or Canonical.
- +
-Intel graphics users need not worry about installing the 3.11 kernel but at the time of writing I was unable to install the non-free Nvidia drivers from the Ubuntu repos for 3.11 and have them work so I was stuck with the considerably less complete and performant Nouveau xorg graphics drivers. I cannot comment on the AMD/Catalyst non-free driver and 3.11 as I have not tried it yet.+
  
 +Intel graphics users need not worry about installing the 3.11 kernel but at the time of writing the Nvidia drivers available in the Ubuntu Precise repos do not support kernel 3.11. This may also be the case for some ATi/AMD Catalyst users. Nvidia 3.11 users must use at least driver version 331.20+ so it is recommended that Nvidia and ATi users who want to fully utilise their hardware wait for newer, 3.11 compatible graphics drivers to make it into the Ubuntu repositories before upgrading. The updated drivers are expected to be available from the repos by March 2014.
 =====Installing a kernel and its headers===== =====Installing a kernel and its headers=====
  
Line 21: Line 20:
 =====Testing kernels===== =====Testing kernels=====
  
-After having installed a new kernel you must rebootand in many cases selectthe new kernel to boot into. Your GRUB boot menu settings are usually updated when you install a new kernel but GRUB doesn't always correctly pick the kernel you want to boot by default. To temporarily boot into a kernel that is not set as GRUB's default you have to hold the left SHIFT key when KXStudio starts booting. This should interrupt the usual boot procedure to display the GRUB menu which lets you use the arrow keys to select a kernel to boot.+After installing a new kernel you must reboot and in many cases you will want to manually select the new kernel to boot into. Your GRUB boot menu settings are usually updated when you install a new kernel but GRUB doesn't always correctly pick the kernel you want to boot by default. 
  
-You can verify the currently running kernel by looking at the System Checks in Cadences main window or running+To temporarily boot into a kernel that is not set as GRUB's default you have to hold the left SHIFT key when KXStudio starts booting. This should interrupt the usual boot procedure to display the GRUB menu which lets you use the arrow keys to select a the kernel or OS to boot. 
 + 
 +You can verify the currently running kernel by looking at the System Checks within Cadence'main window or by running:
  
   uname -a   uname -a
      
-In a terminal.+In a terminal such as Konsole.
  
 =====Changing GRUB's default kernel===== =====Changing GRUB's default kernel=====
  
-We've already mentioned Grub-customizer within this manual and, if you ignore the requirement of having to add its PPA to install it, GC is arguably the easiest way to modify your GRUB settings but there is no need to install that if all you want to do is change the kernel or OS that you want GRUB to boot by default. If we wanted to change GRUB so that it booted the 3.5.0-42-lowlatency kernel we've just installed instead of the default 3.8.0-32-lowlatency, you'd run:+We've already recommended [[https://launchpad.net/grub-customizer|Grub Customizer]] within this manual and, if you ignore the requirement of having to add its PPA to install it, GC is arguably the easiest way to modify your GRUB settings but there is no need to install it if all you want to do is change the kernel or OS that you want GRUB to boot by default.  
 + 
 +To adjust GRUB so that it boots the 3.5.0-42-lowlatency kernel instead of the default 3.8.0-32-lowlatency, you'd run:
  
   kdesudo kate /etc/default/grub   kdesudo kate /etc/default/grub
Line 39: Line 42:
   sudo update-grub   sudo update-grub
   sudo grub-install /dev/sda   sudo grub-install /dev/sda
 +  
 +Then reboot to test your new GRUB settings!
wiki/choosing_and_installing_kernels.1382459156.txt.gz · Last modified: 2013/10/22 18:25 by danboid