2010/7/3 Ralf Mardorf <[email protected]>: > On Fri, 2010-07-02 at 14:51 -0700, Niels Mayer wrote: >> sudo alsa-midi-latency-test -w 20 -r -R -i 36:0 -o 36:0 > > Perhaps better without sudo.
I was just following Paul Davis' lead (*). For me, there's probably no need for this, as my user 'npm' has membership in group jackuser spec'd in /etc/security/limits.conf : > ## Automatically appended by the Planet CCRMA jack-audio-connection-kit > ## NPM changed '*' to @jackuser to limit priority escalation to jackd. > @jackuser - rtprio 99 > @jackuser - memlock 4194304 > @jackuser - nice -10 And /etc/group has entries like: > jackuser:x:476:npm > rtkit:x:470:npm Running as root sidesteps the need for such setup, as well as any permissions issues on the devices under test. From what I can tell, the only privileged access in the test program is indicated by the following output from 'alsa-midi-latency-test': > set_realtime_priority(SCHED_FIFO, 99).. done. ............................. (*): On Fri, Jul 2, 2010 at 4:50 AM, Paul Davis <[email protected]> wrote: > just for comparison, here are the results for an RME Digiface: > sudo /usr/bin/alsa-midi-latency-test -w -r -R -i 20:0 -o 20:0 > ... > best latency was 0.00 ms > worst latency was 1.00 ms, which is great. Better if Paul re-ran the test with "-w 20" argument so his fancypants RME doesn't end up unfairly claiming the 0ms latency title :-) ... Who will claim the low-latency, low-jitter title in this epic battle-of-the-geek: VLSI-implemented midi on the VT1712 or RME's custom FPGA programming?? [[ http://old.nabble.com/Is-RME-HDSPe-AES-supported-by-alsa--td28460997.html ]]. Note that RME's FPGA implemented MIDI and mixer lacks an important feature we get on cheap vt1712 VLSI implementations: MIDI control over the built-in digital mixer via envy24control: http://alsa-tools.sourcearchive.com/documentation/1.0.22-1/midi_8c-source.html (yes there's a built-in midi-controllable, 20 channel, 36-bit digital mixer hidden in that cheap ebay vt1712 -- http://www.via.com.tw/en/products/audio/controllers/envy24/ ). Digital mixing is an important feature of RME's TotalMix : http://www.rme-audio.de/en_support_techinfo.php?page=content/support/en_support_techinfo_hdsp_totalmix_hardware But MIDI control of that mixer seems to be lacking in alsa's hdspmixer and RME's implementation: http://www.rme-audio.de/forum/viewtopic.php?id=6105 -- Niels http://nielsmayer.com PS: worlds' cheapest digital mixing console, take old/slow computer, add linux and these: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=230491593275 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=260501295877 _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/listinfo/linux-audio-dev
