Re: [LAT] [LAD] Patching linux 2.6.26.3 - Linux-audio-tuning

25 Aug 2008

Jussi Laako wrote:
...
  Rui Nuno Capela wrote:
  just tested 2.6.23.3-rt3 here with NO_HZ not set
in my (old) pentium4 
 desktop.

 it just confirmed that NO_HZ is not the culprit here. midi events are 
 still being delivered *completely* out of time and the funny thing is 
 it just gets somewhat better whenever you hit the pc-keyboard keys. 
 however, it all gets back to badness once you stop pressing any key 
 (eg. shift-key)

 another funny thing goes that on a core2 duo T7200 laptop (x86_64) the 
 same kernel config it runs all fine (NO_HZ=y)  
 I'm kind of wondering what these have in
 /sys/devices/system/clocksource/clocksource0/current_clocksource

a) on the desktop (p4(a)2.80C), where midi timing delivery is completely 
broken:

# uname -a
Linux gamma 2.6.26.3-rt3 #1 SMP PREEMPT RT Sat Aug 23 19:34:05 WEST 2008 
i686 i686 i386 GNU/Linux

# cat /sys/devices/system/clocksource/clocksource0/current_clocksource
tsc

b) on the laptop (core2@T7200), where midi seems to work fine:

# uname -a
Linux zeta 2.6.26.3-rt3 #1 SMP PREEMPT RT Sat Aug 23 19:14:58 WEST 2008 
x86_64 x86_64 x86_64 GNU/Linux

# cat /sys/devices/system/clocksource/clocksource0/current_clocksource
hpet

least to say, audio (ie. jackd) works fine on both cases. i've also 
tried to set the clocksource to hpet in a) and got no change in midi/tty 
brokenness.

byee
-- 
rncbc aka Rui Nuno Capela
rncbc(a)rncbc.org