[LAD] Timers, hpet, hrtimer -> kind of solved (for too old motherboards)

Ralf Mardorf ralf.mardorf at alice-dsl.net
Thu Nov 12 13:57:27 UTC 2009

Clemens Ladisch wrote:
> "Busy" means that it's there, but already being used.  Many motherboard
> BIOSes do not initialize the third HPET interrupt, and the first two are
> taken by the kernel.

I would like to make a test song using HR timer, but unfortunately I'm 
not able to close a project and open it again, even after doing a reset.


 From a mail I wrote yesterday to another list:

"the good news is, that using HR timer will cause less jitter than the 
usage of any other timer.
The bad news are
- Open Octave will freeze the system when selecting HR timer
- Qtractor is fine with HR timer, BUT only when I start a project. Once 
I closed it and try to load it again (even after doing a reset) I get 
this error:

"This system has no accessible HPET device (Device or resource busy)"" [1]

" x86_64 and run jackd -Rch -dalsa -dhw:0 -r96000 -p512 -n2 
-Xseq. JACK is jackdmp 1.9.3. The self build kernel might be buggy." [1]

"     ||HR tmr|System|PCM pl|PCM ca
 500.0|| 504.9| 505.6| 503.4| 503.2
                  msec +/- 0.1 msec
maxDif||   6.0|   7.2|   8.8|   9.9
minDif||  -2.7|  -3.2|  -3.4|  -3.2
Jitter||   3.3|   4.0|   5.4|   6.7
                  msec +/- 0.2 msec" [1]

[1] http://lists.64studio.com/pipermail/64studio-users/2009-November/003885.html

More information about the Linux-audio-dev mailing list