Ralf, It depends how ALSA was compiled in the kernel. Here is my kernel config related to this matter:
CONFIG_SND=m CONFIG_SND_TIMER=m CONFIG_SND_PCM=m CONFIG_SND_HWDEP=m CONFIG_SND_RAWMIDI=m CONFIG_SND_SEQUENCER=m CONFIG_SND_SEQ_DUMMY=m # CONFIG_SND_MIXER_OSS is not set # CONFIG_SND_PCM_OSS is not set # CONFIG_SND_SEQUENCER_OSS is not set CONFIG_SND_HRTIMER=m CONFIG_SND_SEQ_HRTIMER_DEFAULT=y J. --- On Sat, 11/7/09, Ralf Mardorf <ralf.mard...@alice-dsl.net> wrote: > From: Ralf Mardorf <ralf.mard...@alice-dsl.net> > Subject: Re: [LAD] timers > To: "James Warden" <warj...@yahoo.com> > Cc: "Emanuel Rumpf" <xb...@web.de>, linux-audio-dev@lists.linuxaudio.org > Date: Saturday, November 7, 2009, 8:36 AM > Thank you Emanuel for this thread :) > thank you James for the information :) > > hopefully this might narrow down my trouble with MIDI > jitter for external equipment, OTOH I don't have any MIDI > jitter for MIDI internal Linux. ALSA MIDI and JACK MIDI > seems to be fine what ever timer I use, this means there is > absolutely no jitter when using a Linux sequencer to control > a Linux synth. Jitter only occurs when using my USB > MIDInterface to control external MIDI equipment. > Unfortunately I can't get my Envy24's MPU working. > > There seems to be no hrtimer available yet: > > $ lsmod | grep snd_hrtimer > $ lsmod | grep timer > snd_timer > 22024 2 snd_pcm,snd_seq > snd > 63800 21 > snd_ice1712,snd_ak4xxx_adda,snd_cs8427,snd_ac97_codec,snd_i2c,snd_mpu401_uart,snd_usb_audio,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_hwdep,snd_seq_oss,snd_rawmidi,snd_seq,snd_timer,snd_seq_device > $ uname -a > Linux 64studio 2.6.29-1-multimedia-amd64 #1 SMP PREEMPT RT > Thu Feb 26 16:18:05 UTC 2009 x86_64 GNU/Linux > > Before I start googleing. Is this a feature for 2.6.31 > only? I'm still not able to boot the .31 kernel-rt from the > Suse 11.2 RC repository and compiling for Suse also failed, > but in the past I never had trouble to build kernel-rt for > Debian/ Ubuntu based 64 Studio. Maybe I should try to build > a kernel .31 for 64 Studio? Or is it just a module I need to > add? Or is my hardware missing something? > > Going to use Google now. > > Bye, > Ralf > > James Warden wrote: > > I forgot to add that snd_hrtimer is used by jackd. > > If I turn jackd off, the snd_hrtimer module is not > used: > > > > $ lsmod | grep timer > > snd_hrtimer > 2148 0 ## <<< not used > > snd_timer > 17408 3 snd_hrtimer,snd_seq,snd_pcm > > > > J. > > > > --- On Sat, 11/7/09, James Warden <warj...@yahoo.com> > wrote: > > > > > >> From: James Warden <warj...@yahoo.com> > >> Subject: Re: [LAD] timers > >> To: "Emanuel Rumpf" <xb...@web.de>, > "Ralf Mardorf" <ralf.mard...@alice-dsl.net> > >> Cc: linux-audio-dev@lists.linuxaudio.org > >> Date: Saturday, November 7, 2009, 7:34 AM > >> Hi guys, > >> > >> Here is what I have: > >> > >> > >> $ cat /proc/asound/timers > >> G0: system timer : 1000.000us (10000000 ticks) > >> G3: HR timer : 0.001us (1000000000 ticks) > >> Client sequencer queue 0 : > running > >> P1-0-0: PCM playback 1-0-0 : SLAVE > >> P1-0-1: PCM capture 1-0-1 : SLAVE > >> > >> Ralf, you do not benefit from a high res timer. > See how > >> much more precise the HR timer is from the output > above. > >> Check which snd timer you have loaded: > >> > >> $ lsmod | grep timer > >> > >> snd_hrtimer > 2148 1 > >> snd_timer > 17408 3 snd_hrtimer,snd_seq,snd_pcm > >> > >> Of course, your h/w should have a HR timer: > >> > >> $ ll /dev/hpet > >> crw-rw---- 1 root audio 10, 228 2009-11-05 12:59 > /dev/hpet > >> > >> you can specify the clock source to jackd: > >> > >> $ jackd --help > >> ... > >> [ --clocksource OR -c [ c(ycle) | h(pet) | > s(ystem) ] > >> ... > >> > >> > >> > >> J. > >> > >> > >> --- On Sat, 11/7/09, Ralf Mardorf <ralf.mard...@alice-dsl.net> > >> wrote: > >> > >> > >>> From: Ralf Mardorf <ralf.mard...@alice-dsl.net> > >>> Subject: Re: [LAD] timers > >>> To: "Emanuel Rumpf" <xb...@web.de> > >>> Cc: linux-audio-dev@lists.linuxaudio.org > >>> Date: Saturday, November 7, 2009, 7:04 AM > >>> Emanuel Rumpf wrote: > >>> > >>>> Hi > >>>> > >>>> I'm confused about all the timers. > >>>> > >>>> There is: > >>>> - system timer > >>>> - hpet (high precision event timer) > >>>> - hr-timer (high resolution timer) > >>>> - rtc (real time clock) > >>>> - cyclic (what's that? a coded loop?) > >>>> - anything else ? > >>>> > >>>> > >>>> What is the relation of all these ? > >>>> Which hardware devices are actually used > by those > >>>> > >> ? > >> > >>>> Which is the prefered timer for sequencing > ? > >>>> > >> hr-timer > >> > >>> / rtc ? > >>> > >>>> > >>> If hardware is fine with Linux real-time > audio, if I > >>> understand correctly, the preferred timer for > MIDI sequencers is > >>> (should be) system timer at ! 1000 Hz ! For my > hardware, that has got > >>> > >> problems > >> > >>> with real-time audio, it's PCM playback and > PCM capture. > >>> > >> Using > >> > >>> this timers MIDI jitter will decrease a little > bit. > >>> > >>> This is the output I get for 64 Studio > 3.0-beta3: > >>> > >>> spinymouse-s...@64studio:~$ cat > /proc/asound/timers > >>> G0: system timer : 1000.000us (10000000 > ticks) > >>> P0-0-0: PCM playback 0-0-0 : SLAVE > >>> P0-0-1: PCM capture 0-0-1 : SLAVE > >>> Client sequencer queue 0 : > stopped > >>> > _______________________________________________ > >>> Linux-audio-dev mailing list > >>> Linux-audio-dev@lists.linuxaudio.org > >>> http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev > >>> > >>> > >> > _______________________________________________ > >> Linux-audio-dev mailing list > >> Linux-audio-dev@lists.linuxaudio.org > >> http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev > >> > >> > > > > > > > > > > -- Secret of Tux: > http://images.wallaceandgromit.com/user_uploads/forum_thumbnails/5/75/355.jpg > "Gromit bit me" says HMV dog: > http://img.dailymail.co.uk/i/pix/2007/03_03/GomitHMVPA_468x319.jpg > > _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
