Rosegarden: System Timer Resolution Too Low

[mkeller]

Whenever I start Rosegarden, I get the following error message:

System timer resolution is too low
Rosegarden was unable to find a high-resolution timing source for MIDI performance.
This may mean you are using a Linux system with the kernel timer resolution set too low. Please contact your Linux distributor for more information.

Sometimes MIDI playback works in Rosegarden, and at other times it doesn't, I think because of the problem listed above. MIDI works fine in KMid and NoteEdit, by the way (thanks to the friendly folks who are the Kubuntu Community), just not always in Rosegarden. Anyone know how to fix this?

[tiger99]

Re: Rosegarden: System Timer Resolution Too Low

If you use Adept to check which kernel is installed, (search for "linux-") you will probably see that "linux-generic" and "linux-image-generic" are installed, plus "linux-headers-2.6......-generic" and "linux-headers-2.6......" as well as a lot of modules etc.

If you see images, headers, etc, suffixed "lowlatency", those are what you probably want to install. Don't remove the originals, certainly not yet, till you know the new kernel works. You should end up with a Grub option to boot the low latency kernel, which ought to solve your problem, provided your hardware is suitable, particularly the motherboard and CPU. I don't know what the minimum requirements are, and introduction of high resolution timers was not necessarily tied directly to CPU speed. But most recent machines will support the low latency kernel properly. I run that, and it has no major drawbacks.

But don't expect the machine to be any faster generally. It will actually be slightly slower overall, when doing computationally intensive tasks, but should will seem to be more responsive to user input. So you might want to keep a generic kernel for booting into to do photo editing, for example, where raw throughput is more important than latency.

There is also a utility called "systune" which you could try first, to see if it allows adjustment of the necessary kernel parameters. It is installable via Adept, but I have no experience of it.

[mkeller]

Re: Rosegarden: System Timer Resolution Too Low

I couldn't figure out how to make systune work, but I installed the lowlatency kernels (thanks for telling me about them, by the way, I thought I'd have to do a compile myself!), and that stops the error popup from popping up.

But some files still don't play audibly. I'm just trying to play the sample files that came with Rosegarden: some, such as bwv-1060-trumpet-duet-excerpt.rg never play, and others, such as bogus-surf-jam.rg sometimes do and sometimes don't. What could be causing this? Anyone else encountered the same thing?