Linux-audio-dev November 2005

linux-audio-dev@lists.linuxaudio.org

51 participants
43 discussions

[linux-audio-dev] Re: [linux-audio-user] jack and setuid

by Jonathan Woithe

Florian Schmidt wrote: > > since i'm using 2.6.14 , you mean set_rtlimits from > > http://www.physics.adelaide.edu.au/~jwoithe/set_rtlimits-1.1.0.tgz ? > > > > but if i run jack as a user, there are no capture ports, and i have tons of > > xruns. > > Just for completeness sake: You can use the realtime lsm for 2.6.13 and > above, too. I would even recommend it, since it's much less of a hassle > to setup (rt_limits being the "correct" solution or not). I'm a bit puzzled by this statement. lsm requires you get the patch, apply it to your kernel, configure and compile your kernel, install and boot the new kernel and then you can start configuring userspace to take advantage of it. In contrast, using the rtlimits approach can be as simple as grabbing set_rtlimits and compiling it (assuming one has a kernel >= 2.6.13 installed of course). Configuring userspace is via a single simple text file (documented in the source distribution). Using it then boils down to doing things like set_rtlimits -r /usr/local/bin/jackd ... set_rtlimits -r /usr/local/bin/ardour etc when starting applications which need it. Aliases can even be used to hide the set_rtlimits bit if desired. To me this seems a *lot* easier than messing around with patched kernels. It *is* true that (on systems which use PAM) PAM can be patched to provide access to the rtlimits functionality in a transparent way. I will admit that doing things this way is complex and a hassle. I wrote set_rtlimits for two reasons: 1) give myself access to the rtlimits functionality - my system doesn't run PAM, so the PAM patches aren't useful to me personally. 2) provide a much simpler way to get access to the rtlimits functionality in this interim period until PAM (or login in the case of systems not using PAM) support rtlimits out the box. set_rtlimits can also control access to the rtlimit resource on a per-program basis. A patched login wouldn't be able to do this; PAM may or may not - I don't know enough about it to comment. Of course everyone is free to choose the solution which best suits them; if people prefer lsm that's fine by me. As a side comment, I'm currently finalising a new version of set_rtlimits. I've generalised it so it can set other resource limits too - locked-in-memory size for example - since this can also be useful to control on a per-program basis. Consequently its name will change to set_rlimits but the version number will be sequential. Invocation has also been made easier (absolute paths will no longer need to be specified - they will be pulled from the configuration file). I expect to have time to finalise it in the next couple of weeks. Best regards jonathan

20 years, 1 month

[linux-audio-dev] the big jack bug... > crappy audio on XRUNS

by federico

it happens randomly, while I play a soft synth, that jack XRUNs once, and the audio become crappy, noisy, like a kinda of digital effect....bit crusher? then all synthesizers (all audio apps) sound the same sh*t... i tried recording with ardour the output, and the output is clean, so I guess is a problem of sync or something that has to do with the hardware (soundcard). in order to record this noise, i had to connect the soundcard output in its input and record it via analog in: http://xaero.ath.cx/jackbug_stereo.wav.bz2 (it is a stereo file, with the clean track panned on the left, and the dirty one on the right). i hope it could be useful to debug the problem... what other information I can provide useful for debug? note that this happens with many version of alsa (1.0.9b, 1.0.10rc2, 1.0.7 or less) and with many kernels (gentoo-sources (slightly patched for speed improvement), ck-sources, ck-sources+realtime-lsm) i hope to solve this problem, since my audio desktop is unusable as si, since audio crasher after playng for just 5 minutes :(

20 years, 1 month

[linux-audio-dev] Re: the big jack bug... > crappy audio on XRUNS

by Luis Garrido

Hi! I had a similar problem in my laptop when using a USB soundcard (Edirol UA-25). For me it was not necessarily associated with xruns. Since ardour doesn't record the noise, I would say that the problem is not in jack, but in the alsa driver. It sounded also more like a distortion than noise, since when the output levels were low the effect was less noticeable. I found empirically that harddisk writing operations like saving a file in an application would sometimes make the distortion stop, I'll be damned if I know why (interrupts?). Anyway, setting my USB unit to work at 48 kHz made this problem practically disappear. HTH, Luis > it happens randomly, while I play a soft synth, that jack XRUNs once, > and the audio become crappy, noisy, like a kinda of digital > effect....bit crusher? > > then all synthesizers (all audio apps) sound the same sh*t... > i tried recording with ardour the output, and the output is clean, so I > guess is a problem of sync or something that has to do with the hardware > (soundcard). > > in order to record this noise, i had to connect the soundcard output in > its input and record it via analog in: > http://xaero.ath.cx/jackbug_stereo.wav.bz2 (it is a stereo file, with > the clean track panned on the left, and the dirty one on the right). > > i hope it could be useful to debug the problem... > what other information I can provide useful for debug? > note that this happens with many version of alsa (1.0.9b, 1.0.10rc2, > 1.0.7 or less) and with many kernels (gentoo-sources (slightly patched > for speed improvement), ck-sources, ck-sources+realtime-lsm) > > i hope to solve this problem, since my audio desktop is unusable as si, > since audio crasher after playng for just 5 minutes :( > >

20 years, 1 month

[linux-audio-dev] Status of mLAN or similar?

by Thomas Vecchione

I am wondering what the status of the mLAN or something similar is in linux? I have been able to find some mention of talking with Yamaha about it, but past that I cant seem to find anything on it. I am looking for a solution to allow me to connect and stream audio in realtime over firewire to a Mac Mini to run some VSTs on until VST support in Linux is worked out completly. Thanks. Seablade

20 years, 1 month

[linux-audio-dev] Re: Radio receiver.

by Juhana Sadeharju

Thanks for the tip on "diversity reception". Yes, I got the idea from astronomer's systems. I use the term "invented" the same way as patenteers: due lack of extensive literary search, I know at most that the thing is new to me. Though, I have never seen such a system used in consumer radios. I'm not sure if it have been used in DX'ing radios either. My test plan was to record the same music station at two cities (apart 200km). Then timescale and align the digitized (1 or 2 hours) recordings manually. And then do the thing. Juhana -- http://music.columbia.edu/mailman/listinfo/linux-graphics-dev for developers of open source graphics software

20 years, 1 month

[linux-audio-dev] [ANN] rt_watchdog

by Florian Schmidt

Hi, here http://affenbande.org/~tapas/rt_watchdog.tgz you find a small program which acts as a watchdog daemon that kills runaway SCHED_FIFO tasks. It does so by setting up two threads: - one high priority (99) consumer that runs every 3 seconds - one low priority (1) producer that runs every second the producer fills a ringbuffer and the consumer drains it. When the ringbuffer runs empty a shell script will be run (via the system() function) that tries to change the scheduling policy of all threads in the system from SCHED_FIFO to SCHED_OTHER. the offending task may naturally not run at prio 99, otherwise the watchdog would never get to run. Here's a potential problem: The shell script potentially changes its own scheduling policy to SCHED_OTHER prior to chnaging the offending runaway task. Ugh! Any hint? Also all IRQ handler threads also have their policy changed. Dunno whether that's good or not. For reference i pasted the script and the c file here: unfifo_stuff.sh (the two arguments are the two thread id's of the rt_watchdog threads, as these are not supposed to have their policy changed). There's also a small test program in the tarball (compiles to test_rt) that wastes cycles SCHED_FIFO (locking the system) but exits eventually, so it's quite safe to test the watchdog with it. Maybe someone else find's it useful. Recommendations, tips, critique are all welcome.. unfifo_stuff.sh #!/bin/bash for i in $( ps -eL -o pid ); do if [ "$i" != "$1" -a "$i" != "$2" ] then chrt -o -p 0 $i fi done rt_watchdog.c: #include <pthread.h> #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <syslog.h> #include <signal.h> #include <sys/mman.h> #include <sys/stat.h> #include <sys/types.h> #include <linux/unistd.h> #include <errno.h> _syscall0(pid_t,gettid) #include "ringbuffer.h" /* how long to sleep between checks in the high prio thread */ #define SLEEPSECS 3 /* how long to sleep between writing "alive" messages to the ringbuffer from the low prio thread */ #define LP_SLEEPSECS 1 /* the priority of the high prio thread */ #define PRIO 99 /* the priority of the low prio thread */ #define LP_PRIO 1 /* the ringbuffer used to transfer "alive" messages from low prio producer to high prio consumer */ jack_ringbuffer_t *rb; pthread_t low_prio_thread; /* the thread id's for the low prio and high prio threads. these get passed to the unfifo_stuff.sh script to make sure the watchdog doesn't repolicy itself to SCHED_OTHER */ pid_t lp_tid; pid_t hp_tid; void signalled(int signal) { } volatile int thread_finish; /* this is the low prio thread. it simply writes to the ringbuffer to signal that it got to run, meaning it is still alive */ void *lp_thread_func(void *arg) { char data; struct timespec tv; lp_tid = gettid(); /* syslog(LOG_INFO, "lp tid: %i", gettid()); */ data = 0 ; while(!thread_finish) { /* we simply write stuff to the ringbuffer and go back to sleeping we can ignore the return value, cause, when it's full, it's ok the data doesn;t have any meaning. it just needs to be there running full shouldn't happen anyways */ jack_ringbuffer_write(rb, &data, sizeof(data)); /* then sleep a bit. but less than the watchdog high prio thread */ tv.tv_sec = LP_SLEEPSECS; tv.tv_nsec = 0; // sleep(LP_SLEEPSECS); nanosleep(&tv, NULL); } return 0; } int main() { pid_t pid, sid; int done; struct sched_param params; char data; int err; int consumed; int count; struct timespec tv; char unfifo_cmd[1000]; /* Fork off the parent process */ pid = fork(); if (pid < 0) { exit(EXIT_FAILURE); } /* If we got a good PID, then we can exit the parent process. */ if (pid > 0) { exit(EXIT_SUCCESS); } /* Change the file mode mask */ umask(0); /* Open any logs here */ openlog("rt_watchdog", 0, LOG_DAEMON); syslog(LOG_INFO, "started"); /* Create a new SID for the child process */ sid = setsid(); if (sid < 0) { /* Log any failure here */ syslog(LOG_INFO, "setsid failed. exiting"); exit(EXIT_FAILURE); } /* Change the current working directory */ if ((chdir("/")) < 0) { /* Log any failure here */ syslog(LOG_INFO, "chdir failed. exiting"); exit(EXIT_FAILURE); } /* Close out the standard file descriptors */ close(STDIN_FILENO); close(STDOUT_FILENO); close(STDERR_FILENO); // syslog(LOG_INFO, "closed fd's"); /* syslog(LOG_INFO, "hp tid: %i", gettid()); */ hp_tid = gettid(); /* not really nessecary, but wtf */ mlockall(MCL_FUTURE); thread_finish = 0; done = 0; /* get ourself SCHED_FIFO with prio PRIO */ params.sched_priority = PRIO; if (pthread_setschedparam(pthread_self(), SCHED_FIFO, &params)) { syslog(LOG_INFO, "couldn't set realtime prio for main thread.. exiting.."); exit(EXIT_FAILURE); } // syslog(LOG_INFO, "prio set"); /* create a ringbuffer for the low prio thread to signal it's alive */ rb = jack_ringbuffer_create(1024); // syslog(LOG_INFO, "ringbuffer created"); /* create low prio thread */ err = pthread_create(&low_prio_thread, 0, lp_thread_func, 0); if(err) { syslog(LOG_INFO, "couldn't create low prio thread, exiting.."); exit(EXIT_FAILURE); } /* dirty. we really need to wait for the lp thread to have written the lp_tid. (condition variable?) */ sleep(1); // syslog(LOG_INFO, "created low prio thread"); /* make the low prio thread sched_fifo */ params.sched_priority = LP_PRIO; if (pthread_setschedparam(low_prio_thread, SCHED_FIFO, &params)) { syslog(LOG_INFO, "couldn't set realtime prio for lower prio thread.. exiting.."); thread_finish = 1; pthread_join(low_prio_thread, NULL); exit(EXIT_FAILURE); } /* this is the main loop. we somply check whether the low prio thread got to run at all by looking into the ringbuffer. If it's empty, the low prio thread is kinda dead */ count = 0; while(!done) { tv.tv_sec = SLEEPSECS; tv.tv_nsec = 0; nanosleep(&tv, NULL); /* sleep(SLEEPSECS); */ count++; /* syslog(LOG_INFO, "count %i", count); */ /* see if our little brother got to run */ if (jack_ringbuffer_read_space(rb) == 0) { /* oh oh, it didn't */ syslog(LOG_INFO, "low prio thread seems to be starved, taking measures..."); /* we pass our own TID's to the script, so we are excluded from the scheduling policy change */ sprintf(unfifo_cmd, "unfifo_stuff.sh %i %i", lp_tid, hp_tid); syslog(LOG_INFO, "unfifo command:"); syslog(LOG_INFO, unfifo_cmd); if (system(unfifo_cmd) == -1) { syslog(LOG_INFO, "unfifo command failed"); } } else { /* consume stuff from ringbuffer */ consumed = 0; while (jack_ringbuffer_read_space(rb)) { consumed++; jack_ringbuffer_read(rb, &data, 1); } /* syslog(LOG_INFO, "lp alive: %i", consumed); */ } } thread_finish = 1; pthread_join(low_prio_thread, NULL); syslog(LOG_INFO, "exiting"); exit(EXIT_SUCCESS); } test.c: #include <pthread.h> #include <stdlib.h> #include <sys/time.h> #include <time.h> int main() { struct sched_param params; int done = 0; struct timeval tv; time_t startsec; unsigned long int loops; int outer_loops; params.sched_priority = 80; pthread_setschedparam(pthread_self(), SCHED_FIFO, &params); gettimeofday(&tv,0); startsec = tv.tv_sec; #if 0 while(!done) { gettimeofday(&tv, 0); if(tv.tv_sec - startsec > 10) done = 1; } #endif for (outer_loops = 0; outer_loops < 4; ++outer_loops) { for (loops = 0; loops < 1000000000; loops++) {done += 1;} } exit (EXIT_SUCCESS); } -- Palimm Palimm! http://tapas.affenbande.org

20 years, 1 month

[linux-audio-dev] [ANN] DRC 2.6.1

by Denis Sbragion

Hello Everybody, DRC 2.6.1 is available at: http://sourceforge.net/project/showfiles.php?group_id=136217 and soon it will be announced at the usual: http://freshmeat.net/projects/drc/ Changes: Minor corrections and improvements have been applied to the documentation and to the pre-echo truncation inversion procedure. A new target transfer function definition procedure based on Uniform B Splines has been introduced. The development environment has been moved to Code::Blocks and GCC/MinGW. Best of listening, -- Denis Sbragion InfoTecna Tel: +39 0362 805396, Fax: +39 0362 805404 URL: http://www.infotecna.it

20 years, 1 month

[linux-audio-dev] [ANN] Denemo 0.7.4 Released

by Adam Tee

Denemo is a GTK+ front end for GNU Lilypond Music Typesetter. http://denemo.sourceforge.net After a long period of time denemo 0.7.4 has been released. New features include : Help Documentation Support for exporting to Lilypond 2.6 All ornaments/articulations added Replace Mode Basic Redo/Undo Functionality for individual objects More Templates available Export to PDF (via lilypond processing) Courtesy of Jens Askengren Also, this mail serves as a call for additional contributors to the project as Lilypond is fast moving rapid development is required to keep up. A plug-in API is being developed to enable export to other file formats or automated composition tools. Any contribution will be greatly received. Adam

20 years, 1 month

[linux-audio-dev] digigram mixart cards in smp machine

by Eric Dantan Rzewnicki

I'm trying to get a digigram mixart8 aes/ebu working in a dual xeon box. A RME digi96 card works fine in the same box and the digigram works fine in a different uni-processor box. I don't know if it's smp related or just the box or what. booting with nosmp does not help. The symptom is that aplay fails with EINVAL when trying to open /dev/snd/pcmC0D0p (or any other device on the card). jackd fails similarly when trying to open the corresponding capture device. Elrond:~# aplay /var/snd/999999_000.wav aplay: main:533: audio open error: Invalid argument The firmware is loaded. aplay works on the same box with the RME card. This is debian sarge with 2.6.13 (also tried 2.6.14) and alsa 1.0.9. Anyone have any thoughts? -- Eric Dantan Rzewnicki | Systems Administrator Technical Operations Division | Radio Free Asia 2025 M Street, NW | Washington, DC 20036 | 202-530-4900 CONFIDENTIAL COMMUNICATION This e-mail message is intended only for the use of the addressee and may contain information that is privileged and confidential. Any unauthorized dissemination, distribution, or copying is strictly prohibited. If you receive this transmission in error, please contact network(a)rfa.org.

20 years, 1 month

[linux-audio-dev] jack and setuid

by conrad berhörster

Hello Lists, I don't know, where ich can fix my little problem. Maybe i 've missed some explanations and/or haven't read my mails good enough. anyway, i try to install a linuxbox for audio on slackware i have installed slackware and patching the kernel 2.6.14 vanilla with patch-2.6.14-rt2. Then i installed the set_rtlimits1.1.0 software, because Slackware has no PAM. First. this must be all for audio in realtime , is this right?? then i have to set the setuid. aus root i have done bash-3.00$ su Password: bash-3.00# chmod ugo+s /usr/local/bin/jackd bash-3.00# exit bash-3.00$ ls -la /usr/local/bin/jackd -rwsr-sr-x 1 root root 206476 2005-11-01 15:23 /usr/local/bin/jackd bash-3.00$ whoami soundroom bash-3.00$ jackd -dalsa& [1] 3202 bash-3.00$ jackd 0.100.0 Copyright 2001-2005 Paul Davis and others. jackd comes with ABSOLUTELY NO WARRANTY This is free software, and you are welcome to redistribute it under certain conditions; see the file COPYING for details JACK compiled with System V SHM support. loading driver .. creating alsa driver ... hw:0|hw:0|1024|2|48000|0|0|nomon|swmeter|-|32bit control device hw:0 configuring for 48000Hz, period = 1024 frames, buffer = 2 periods nperiods = 2 for capture nperiods = 2 for playback bash-3.00$ ps -aux [..] root 3202 0.0 0.4 10472 2380 pts/1 S 12:03 0:00 jackd -dalsa root 3203 0.0 0.4 10472 2380 pts/1 R 12:03 0:00 jackd -dalsa root 3204 0.0 0.4 10472 2380 pts/1 S 12:03 0:00 jackd -dalsa root 3205 0.0 0.4 10472 2380 pts/1 S 12:03 0:00 jackd -dalsa root 3206 0.2 0.4 10472 2380 pts/1 S 12:03 0:00 jackd -dalsa [..] bash-3.00$ jack_lsp JACK server not running why i can't use jack an normal user? what have i missed? why there are 5 processes of jack? is this a secure way? do i need every application as suid?

20 years, 1 month

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Linux-audio-dev November 2005