JackAudio March 2018

jackaudio@lists.linuxaudio.org

14 participants
10 discussions

by Stefan Hellkvist

Hi list, (Sorry this question has already been discussed but the search function in the archive of the list does not work) Is anyone working on the problem of getting Jack up and running on MacOS again? I installed Jack with brew but I get these “could not handle external client request” errors which seems to be old problems from looking at search results and GitHub discussions - problems introduced when MacOS audio architecture was changed a while back. Is there any progress on these matters? Is someone working on it? I need Jack as it is a dependency to another library I would like to use but I realize that I might have to abandon MacOS as a platform in the process. Kindest regards, Stefan

5 years, 6 months

Re: [Jack-Devel] AES67 / SMPTE ST 2110-30

by happy musicmaker

That is such good news. What(low cost) hardware would this development be used on to support the developers with testing/debugging and maybe even development ? * MOTU LP32 (Preferred) * MiniDSP https://www.minidsp.com/products/network-audio/avb-dg (I think MOTU's switch uses midDSP switch hardware) I hope someday it will be possible to connect 4 or more 8 channel ADAT modules (32 channels) to a PC under Ubuntu via AVB with low latency. The only option to get this done under Windows is a Focursrite DANTE based Rednet 3 right now because Thunderbolt is not really available there as well. Plan to get Rednet3, but that does not solve the Linux environment which I prefer. Would love to be able to use the Rednet 3 under Linux but since DANTE is proprietary , so unlikely. My two wishes: [a] Multi (16+) channel low latency audio I/O using ADAT audio AD/DA [b[ Bitwig supporting LV2 plugins. With those two, the Linux Audio environment would be perfect and the world a better place. *(Apology for the re-sends and ignore the previous edits. Web based Gmail is such a annoyance and un-logically structured)*

6 years, 3 months

Re: [Jack-Devel] Fwd: connecting to JACKD2 with low buffer sizes

by Chris Caudle

On Mon, March 26, 2018 9:38 am, Christopher Obbard wrote: > Big typo! I am running on a TI 1GHz AM3358 processor. Ok, three orders of magnitude is a pretty significant difference. So is this a BeagleBone Black or something similar? If so I run the RT kernels from the RCN repo, never had any problem with those so might be a good starting point. > I've been using CONFIG_PREEMPT also in other places, I have been > wondering whether the full RT patch will cause less throughput for > the jack process. The design of jackd is not about throughput, it is about low latency. If you want better throughput, use larger period sizes. That is not really specific to jack, that is just a general principle in computing, if you want the best throughput using a general purpose computer design you should bundle your data into larger groups so that the processor has to handle fewer interrupts and the DMA controller(s) can run in the most efficient configuration. If you want the lowest latency you will have to trade off some throughput for that. If you want really low latency and high throughput you will likely have to design custom hardware with pipelined processing (e.g. some of the cut-through switch designs used for Infiniband and very low latency HPC Ethernet switches). That is a more advanced topic than how to get jackd running on an off the shelf processor. > Both jack and my application are requesting SCHED_FIFO, I am not sure > of the priority of the application but I am thinking of setting them both to 70-80. Why not start off reading the linux audio and jack FAQs that explain how you should configure your RT system? It sounds like you are getting ready to re-discover all of that information the long and hard way. Might be entertaining and educational but probably is no the best use of your time. http://jackaudio.org/faq/linux_rt_config.html http://jackaudio.org/faq/linux_group_sched.html I thought there was a page somewhere with suggestions on RT priority settings, but I do not see it on the jackaudio FAQ or wiki pages. The rtirq script from Rui might be useful: http://www.rncbc.org/jack/ (link is toward the bottom) There may be some useful info here: https://wiki.linuxaudio.org/wiki/system_configuration but unfortunately the low latency page is from 2000, there have been quite a few changes in kernel setup since then, so I don't know how useful the low latency wiki page actually is on linuxaudio.org these days. The short version is you want the interrupt for your sound hardware to be highest, then jack right after that. There probably won't be any other RT tasks on a single use system, so it probably won't matter whether you set the sound IRQ and jackd priorities to 90 and 89, or 70 and 69, just make sure they are higher than the default for non-RT tasks, which I think is 50. The applications using jackd actually run the RT audio thread in jackd context, so unless I misunderstood something it should not in principle matter what the priority of the (main thread) of the other applications is set. > What about HZ, I currently have this set to HZ_100. Would HZ_1000 be any better? Could be better for scheduling latency, but for IRQ driven tasks like handling the sound hardware I don't know if it matters or not. >> What audio hardware are you running? >> Are you using an ALSA driver from the current kernel tree? > > It's an 6-channel in, 6-channel out card with a simple ALSA driver written by me. There appears to be a TI McASP driver in the kernel tree already, any reason you are not using that? Just asking, I have not tried to base anything on that driver yet myself. http://processors.wiki.ti.com/index.php/Sitara_Linux_Audio_Driver_Overview >From that page it appears you would just need to write the codec driver that handles specifics of the platform driver settings needed, and any control interfaces. > The driver just binds the codecs to the CPU, nothing latent in there. > All of the FIFO stuff is taken care of by the TI McASP driver. OK, it sounds like maybe that is actually what you did, just wrote the codec portion and used the existing McASP driver to handle the I2S/TDM interface pieces. > Currently the driver reads & writes to 8 channels but two of the > out channels are unused, I can possibly try to gain some > performance here. Not worth the trouble at this point. If you get a system that is mostly working and just has an occasional problem it might be worth optimizing, but it sounds like right now the system is pretty broken, so look for big problems, not small optimizations you could make. > Sorry, I missed out the first part of the log. The LockedTimedWait > error came when my client tried to connect. I think it's to do > with the Kernel scheduling. Make sure you have RT scheduling enabled for whatever user account you are using, try again and get the entire startup log. > It manages to open and all performs fine at 128 frames. OK, then make sure you are really clear about when you are trying to debug problems with e.g. 32 frame setting vs. problems with the 128 frames setting, since it looks like you have different problems with the different period sizes. > I've not had much luck with PREEMPT_RT in the past, I don't > think I've set the priorities of interrupts properly. Then start with Rui's rtirq script. Some of the devices in the default script are x86 specific, and even some of those are probably outdated, but the framework is great, put the devices you want in the configuration file and run the script, it will set everything for you. > I think I need to chrt the soundcard IRQ highest, then JACK, then my application.... > AFAIK, jack already does this with the -R argument & sets the > scheduler priority to SCHED_FIFO. I don't think the application RT priority matters, if I understand correctly jackd will be allocating the thread that the application uses for audio callback, so that thread of the application should run at jackd priority, so for a simple embedded system you would just need to set the sound hardware IRQ the highest, then jackd after that (with the -R argument, default values is probably OK), then everything else can run at non-RT default. I think non-RT default is 50 and jackd default is 70 based on what I have seen on x86 machines. > Have you got any links to information, books etc on RT patch? Just this, but honestly the original jackd developers took care of almost everything for you, you shouldn't need to know much about the low level details just to get it running. https://wiki.linuxfoundation.org/realtime/documentation/start -- Chris Caudle

6 years, 7 months

[Jack-Devel] Fwd: connecting to JACKD2 with low buffer sizes

by Christopher Obbard

Hi Guys, Running jack with a small buffer (-p64 -n2), and connecting with any client causes issues. With higher buffer sizes, all is OK. This is on an ARM embedded system, with a single core 1MHz processor. I've set the cpu governor to performance. I have a custom compiled 4.14 kernel with omap2plus_defconfig with the following config settings: > CONFIG_PREEMPT_VOLUNTARY=y > HZ_100=y > CONFIG_NO_HZ_IDLE=y $ jackd -R -P95 -dalsa -dhw:0 -r48000 -p64 -n2 > JackPosixProcessSync::LockedTimedWait error usec = 5000000 err = Connection timed out > Driver is not running > Cannot create new client > CheckSize error size = 32 Size() = 12 > CheckRead error > CheckSize error size = -1 Size() = 4 > CheckRead error > CheckSize error size = 0 Size() = 12 > CheckRead error Also, with higher buffer sizes sometimes I get xruns. After enabling alsa debugging, the error is: > ALSA: PCM: [Q] Lost interrupts?: (stream=0, delta=221, new_hw_ptr=181343, old_hw_ptr=181122) Loosing the FIFO interrupts doesn't seem like a great thing......... I _think_ the issue is to do with the kernel scheduling, but this why I ask the experts :-). Can anyone suggest any kernel settings that will improve my situation? Many thanks, Chris

6 years, 7 months

[Jack-Devel] Compiling, Debuging and Running Jack2 with WAF

by DaemoniumAer

Hello, I am working on Arch Linux and use gcc and gdb, my current IDE is Visual Studio Code. Can someone help me with how to use waf? It let's me configure, build and install... but what if I want to test a change in code? I made a short script wich unistalled, built and installed jack2 again so I could see the change, but is there another way like executing jackd in the build dir? How about cross-compiling to another architecture? I couldn't find anything allowing me to do that. And how do you debug a program like this? I only have experience with small projects and it's really hard to find anything about it on the internet. Sorry if this may end up being a stupid question but I have been spending weeks trying to figure this out. Kind regards, Ariel -- Sent from: http://jack-audio.10948.n7.nabble.com/Jackit-f3.html

6 years, 7 months

[Jack-Devel] Processing multichannel inputs in JACK

by Benny Alexandar

Hi, I have a requirement to process and analyze more than 5 audio stereo inputs simultaneously capture and analyze using a client program. How it can be achieved with JACK. -ben

6 years, 7 months

[Jack-Devel] libjack.so and libjackserver.so bug

by Christoph Kuhr

Hi *, I observed some strange behavior of libjack and libjackserver. If I have a multiprocessing application with one jack server fork and one jack client fork, jack_client_open crashs. Here the backtrace: #0 __strcmp_ssse3 () at ../sysdeps/x86_64/multiarch/../strcmp.S:174 #1 0x00007f83dddb803f in jack_find_driver_descriptor(_JSList*, char const*) () from /usr/local/lib/libjackserver.so.0 #2 0x00007f83dddb9ef8 in Jack::JackServerGlobals::Init() () from /usr/local/lib/libjackserver.so.0 #3 0x00007f83dddb64f8 in jack_client_open_aux(char const*, JackOptions, JackStatus*, __va_list_tag*) () from /usr/local/lib/libjackserver.so.0 #4 0x00007f83dddb67b1 in jack_client_open () from /usr/local/lib/libjackserver.so.0 #5 0x0000000000414f04 in talker_Process (arguments=0x63f680 <arguments>) at ../src/net/avb/talker/talker_process.c:395 #6 0x000000000042d487 in avbruntime (arguments=0x63f680 <arguments>) at ../src/avbruntime.c:644 #7 0x000000000042e888 in main (argc=11, argv=0x7ffebee6f678) at ../src/main.c:144 The interesting thing is, jack_client_open keeps crashing if I remove all the jack server code. It was neccessary to remove the -ljackserver linker option as well, because the client code linked against libjackserver.so instead of libjack.so. This means it is not possible to have a jack server and a jack client in a single multiprocessing application. BR, Ck

6 years, 7 months

[Jack-Devel] FFADO 2.4.1 released

by Jonathan Woithe

FFADO version 2.4.1 is now available, a package of userspace drivers for firewire audio interfaces. This is a bugfix release with many of the changes associated with the use of python3 and distribution packaging. This is a source-only release which can be downloaded from the ffado.org website at http://ffado.org or via the direct link: http://ffado.org/files/libffado-2.4.1.tgz Issues addressed in this release include: * Fix some python syntax which was not compatible with python3. These were missed during the preparation of FFADO 2.4.0. * Modify the SCons build system to allow for scons running under python3. As of this release there seem to be a number of issues in scons itself when running under python3, so building FFADO in this environment is not yet guaranteed. * Merge distribution patches provided by package maintainers. * Address some difficulties experienced by package maintainers when compiling FFADO. * Improve the output of ffado-diag. Thanks to the developers and users who contributed to this release: Nicolas Bouleng, Benoit Delcour, David Kastrup, Hector Martin, Orcan Ogetbil, Dave Plater, David Runge, Jano Svitok and Jonathan Woithe. If an omission has been made please contact us through the ffado-devel mailing list so this can be corrected.

6 years, 8 months

[Jack-Devel] Multiprocessing Program with JACK Server and two Clients - Clients fail with Driver not running

by Christoph Kuhr

HI *, I have a multiprocessing program that shall host a JACK server and two JACK clients. The server is named "AVB_Processing", the clients are name "AVB_Talker" and "AVB_Listener". The JACK server is created and started before forking the other processes and looks fine: JACK server starting in realtime mode with priority 8 self-connect-mode is "Don't restrict self connect requests" Jack: JackPosixThread::StartImp : create non RT thread Jack: JackPosixThread::ThreadHandler : start Jack: playback device hw:1,0 Jack: capture device hw:1,0 Jack: capture device hw:1,0 Jack: playback device hw:1,0 Jack: apparent rate = 48000 Jack: frames per period = 128 Jack: JackDriver::Open capture_driver_name = hw:1,0 Jack: JackDriver::Open playback_driver_name = hw:1,0 Jack: Check protocol client = 8 server = 8 Jack: JackEngine::ClientInternalOpen: name = system Jack: JackEngine::AllocateRefNum ref = 0 Jack: JackLinuxFutex::Allocate name = jack_sem.0_AVB_Processing_system val = 0 Jack: JackEngine::NotifyAddClient: name = system Jack: JackGraphManager::SetBufferSize size = 128 Jack: JackConnectionManager::DirectConnect first: ref1 = 0 ref2 = 0 Jack: JackGraphManager::ConnectRefNum cur_index = 0 ref1 = 0 ref2 = 0 Jack: JackDriver::SetupDriverSync driver sem in flush mode creating alsa driver ... hw:1,0|hw:1,0|128|2|48000|2|2|nomon|swmeter|-|32bit configuring for 48000Hz, period = 128 frames (2.7 ms), buffer = 2 periods ALSA: final selected sample format for capture: 32bit integer little-endian ALSA: use 2 periods for capture ALSA: final selected sample format for playback: 32bit integer little-endian ALSA: use 2 periods for playback Jack: JackSocketServerChannel::Open Jack: JackServerSocket::Bind : addr.sun_path /dev/shm/jack_AVB_Processing_0_0 Jack: JackSocketServerChannel::BuildPoolTable size = 1 Jack: JackEngine::Open Jack: JackClientSocket::Connect : addr.sun_path /dev/shm/jack_AVB_Processing_0_0 Jack: JackEngine::ClientInternalOpen: name = freewheel Jack: JackEngine::AllocateRefNum ref = 1 Jack: JackLinuxFutex::Allocate name = jack_sem.0_AVB_Processing_freewheel val = 0 Jack: JackEngine::NotifyAddClient: name = freewheel Jack: JackDriver::ClientNotify ref = 1 driver = system name = freewheel notify = 0 Jack: JackDriver::ClientNotify ref = 0 driver = freewheel name = system notify = 0 Jack: JackConnectionManager::DirectConnect first: ref1 = 1 ref2 = 1 Jack: JackGraphManager::ConnectRefNum cur_index = 0 ref1 = 1 ref2 = 1 Jack: JackDriver::SetupDriverSync driver sem in flush mode Jack: JackGraphManager::SetBufferSize size = 128 Jack: JackAlsaDriver::Attach fBufferSize 128 fSampleRate 48000 Jack: JackEngine::PortRegister ref = 0 name = system:capture_1 type = 32 bit float mono audio flags = 22 buffer_size = 128 Jack: JackGraphManager::AllocatePortAux port_index = 1 name = system:capture_1 type = 32 bit float mono audio Jack: JackConnectionManager::AddOutputPort ref = 0 port = 1 Jack: JackEngine::ClientNotify: no callback for notification = 9 Jack: JackEngine::ClientNotify: no callback for notification = 9 Jack: JackAlsaDriver::Attach fCapturePortList[i] 1 Jack: JackEngine::PortRegister ref = 0 name = system:capture_2 type = 32 bit float mono audio flags = 22 buffer_size = 128 Jack: JackGraphManager::AllocatePortAux port_index = 2 name = system:capture_2 type = 32 bit float mono audio Jack: JackConnectionManager::AddOutputPort ref = 0 port = 2 Jack: JackEngine::ClientNotify: no callback for notification = 9 Jack: JackEngine::ClientNotify: no callback for notification = 9 Jack: JackAlsaDriver::Attach fCapturePortList[i] 2 Jack: JackEngine::PortRegister ref = 0 name = system:playback_1 type = 32 bit float mono audio flags = 21 buffer_size = 128 Jack: JackGraphManager::AllocatePortAux port_index = 3 name = system:playback_1 type = 32 bit float mono audio Jack: JackConnectionManager::AddInputPort ref = 0 port = 3 Jack: JackEngine::ClientNotify: no callback for notification = 9 Jack: JackEngine::ClientNotify: no callback for notification = 9 Jack: JackAlsaDriver::Attach fPlaybackPortList[i] 3 Jack: JackEngine::PortRegister ref = 0 name = system:playback_2 type = 32 bit float mono audio flags = 21 buffer_size = 128 Jack: JackGraphManager::AllocatePortAux port_index = 4 name = system:playback_2 type = 32 bit float mono audio Jack: JackConnectionManager::AddInputPort ref = 0 port = 4 Jack: JackEngine::ClientNotify: no callback for notification = 9 Jack: JackEngine::ClientNotify: no callback for notification = 9 Jack: JackAlsaDriver::Attach fPlaybackPortList[i] 4 Jack: Clock source : hpet Jack: JackServer::Start Jack: JackThreadedDriver::Start Jack: JackPosixThread::StartImp : create non RT thread Jack: JackPosixThread::ThreadHandler : start Jack: JackThreadedDriver::Init real-time Jack: JackPosixThread::AcquireRealTimeImp priority = 8 Jack: JackPosixThread::StartImp : create non RT thread Jack: JackPosixThread::ThreadHandler : start Jack: JackSocketServerChannel::ClientCreate socket Jack: JackSocketServerChannel::BuildPoolTable size = 2 Jack: JackSocketServerChannel::BuildPoolTable fSocketTable i = 1 fd = 56 Jack: JackSocketServerChannel::Execute : fPollTable i = 1 fd = 56 Jack: JackRequest::Notification Jack: JackDriver::ClientNotify ref = 1 driver = freewheel name = freewheel notify = 18 Jack: JackDriver::ClientNotify ref = 1 driver = freewheel name = freewheel notify = 18 Jack: JackDriver::ClientNotify ref = 1 driver = freewheel name = freewheel notify = 18 Jack: JackDriver::ClientNotify ref = 1 driver = freewheel name = freewheel notify = 18 Jack: JackEngine::ClientNotify: no callback for notification = 4 Jack: JackEngine::ClientNotify: no callback for notification = 4 Jack: **** alsa_pcm: xrun of at least -5118090.752 msecs Jack: ALSA XRun wait_status = 0 Jack: JackSocketServerChannel::Execute : fPollTable i = 1 fd = 56 Jack: JackRequest::Notification Jack: JackEngine::ClientNotify: no callback for notification = 3 Jack: JackEngine::ClientNotify: no callback for notification = 3 Jack: **** alsa_pcm: xrun of at least -5118163.456 msecs Jack: ALSA XRun wait_status = 0 Jack: JackSocketServerChannel::Execute : fPollTable i = 1 fd = 56 Jack: JackRequest::Notification Jack: JackEngine::ClientNotify: no callback for notification = 3 Jack: JackEngine::ClientNotify: no callback for notification = 3 After the JACK server is running, I fork four processes. Two of which try to open a JACK client without success: Jack: jack_client_open AVB_Talker Jack: JackInternalClient::Open name = AVB_Talker Jack: Check protocol client = 8 server = 8 Jack: JackEngine::ClientInternalOpen: name = AVB_Talker Jack: JackEngine::AllocateRefNum ref = 2 Jack: JackLinuxFutex::Allocate name = jack_sem.0_AVB_Processing_AVB_Talker val = 0 Jack: JackPosixProcessSync::TimedWait time out = 5000000 Jack: jack_client_open AVB_Listener Jack: JackInternalClient::Open name = AVB_Listener Jack: Check protocol client = 8 server = 8 Jack: JackEngine::ClientInternalOpen: name = AVB_Listener Jack: JackEngine::AllocateRefNum ref = 2 Jack: JackLinuxFutex::Allocate name = jack_sem.0_AVB_Processing_AVB_Listener val = 0 Jack: JackPosixProcessSync::TimedWait time out = 5000000 JackPosixProcessSync::LockedTimedWait error usec = 5000000 err = Connection timed out Jack: JackPosixProcessSync::TimedWait finished delta = 5000078.0 Driver is not running Cannot open client name = AVB_Talker JackPosixProcessSync::LockedTimedWait error usec = 5000000 err = Connection timed out Jack: JackPosixProcessSync::TimedWait finished delta = 5000069.0 Driver is not running Cannot open client name = AVB_Listener Jack: JackSocketServerChannel::Execute : fPollTable i = 1 fd = 56 The client probably fails with "Driver is not running" due to the ALSA xruns of the server: Jack: **** alsa_pcm: xrun of at least -5118090.752 msecs Jack: ALSA XRun wait_status = 0 Jack: JackSocketServerChannel::Execute : fPollTable i = 1 fd = 56 Jack: JackRequest::Notification Jack: JackEngine::ClientNotify: no callback for notification = 3 Jack: JackEngine::ClientNotify: no callback for notification = 3 Jack: **** alsa_pcm: xrun of at least -5118163.456 msecs Jack: ALSA XRun wait_status = 0 Here is the server code: static void set_jack_server_parameters( FILE* filepointer, const JSList * node_ptr) { while (node_ptr != NULL) { jackctl_parameter_t * parameter = (jackctl_parameter_t *)node_ptr->data; if( ( strcmp( jackctl_parameter_get_name(parameter), "rate" ) == 0 ) || ( strcmp( jackctl_parameter_get_name(parameter), "period" ) == 0 ) || ( strcmp( jackctl_parameter_get_name(parameter), "nperiods" ) == 0 ) || ( strcmp( jackctl_parameter_get_name(parameter), "device" ) == 0 ) || ( strcmp( jackctl_parameter_get_name(parameter), "realtime-priority" ) == 0 ) || ( strcmp( jackctl_parameter_get_name(parameter), "realtime" ) == 0 ) || ( strcmp( jackctl_parameter_get_name(parameter), "inchannels" ) == 0 ) || ( strcmp( jackctl_parameter_get_name(parameter), "outchannels" ) == 0 ) || ( strcmp( jackctl_parameter_get_name(parameter), "playback" ) == 0 ) || ( strcmp( jackctl_parameter_get_name(parameter), "capture" ) == 0 ) || ( strcmp( jackctl_parameter_get_name(parameter), "verbose" ) == 0 ) || ( strcmp( jackctl_parameter_get_name(parameter), "clock-source" ) == 0 ) || ( strcmp( jackctl_parameter_get_name(parameter), "name" ) == 0 ) ){ union jackctl_parameter_value value; if( ( strcmp( jackctl_parameter_get_name(parameter), "name" ) == 0 ) ){ sprintf( value.str, "AVB_Processing"); } else if( ( strcmp( jackctl_parameter_get_name(parameter), "verbose" ) == 0 ) ){ value.b = true; } else if( ( strcmp( jackctl_parameter_get_name(parameter), "clock-source" ) == 0 ) ){ value.ui = 1; } else if( ( strcmp( jackctl_parameter_get_name(parameter), "rate" ) == 0 ) ){ value.ui = 48000; } else if( ( strcmp( jackctl_parameter_get_name(parameter), "period" ) == 0 ) ){ value.ui = 128; } else if( ( strcmp( jackctl_parameter_get_name(parameter), "nperiods" ) == 0 ) ){ value.ui = 2; } else if( ( strcmp( jackctl_parameter_get_name(parameter), "device" ) == 0 ) ){ sprintf( value.str, "hw:1,0"); } else if( ( strcmp( jackctl_parameter_get_name(parameter), "realtime-priority" ) == 0 ) ){ value.i = 8; } else if( ( strcmp( jackctl_parameter_get_name(parameter), "realtime" ) == 0 ) ){ value.b = true; } else if( ( strcmp( jackctl_parameter_get_name(parameter), "inchannels" ) == 0 ) ){ value.ui = 2; } else if( ( strcmp( jackctl_parameter_get_name(parameter), "outchannels" ) == 0 ) ){ value.ui = 2; } jackctl_parameter_set_value( parameter, &value ); } node_ptr = jack_slist_next(node_ptr); } } if( (server = jackctl_server_create(NULL, NULL) )); parameters = jackctl_server_get_parameters(server); set_jack_server_parameters(filepointer, parameters); drivers = jackctl_server_get_drivers_list(server); node_ptr = drivers; while (node_ptr != NULL) { if( ( strcmp( jackctl_driver_get_name((jackctl_driver_t *)node_ptr->data), "alsa" ) == 0 ) ){ set_jack_server_parameters( filepointer, jackctl_driver_get_parameters( ( jackctl_driver_t *) node_ptr->data) ); } node_ptr = jack_slist_next(node_ptr); } if( (jackctl_server_open(server, jackctl_server_get_driver(server, "alsa")) )); if( (jackctl_server_start(server) )); Jack is working fine outside my program. I cloned the git repo of jack2 today ( jackdmp 1.9.12 ). What might be going wrong here? Thanks, Ck

6 years, 8 months

[Jack-Devel] The playback device hw:0 is already in use

by Tim Janes

I am new to jack and trying to setup Jack2 on Ubuntu 17.10 on a Dell laptop 15-5570 that uses a Realtek ALC3246 sound device. It is basically working ( I am testing it with simple_client and latent_client) but I think that I am doing something wrong as the first time I use it after booting the laptop I get the error. "ATTENTION: The playback device "hw:0" is already in use. Please stop the application using it and run JACK again" followed by lots of "Cannot connect to server socket err = No such file or directory" "Cannot connect to server request channel" fuser -v /dev/snd/pcmC0D0p shows that it is use by pulseaudio. However the 2nd and subsequent runs of the jack example clients work just fine without any error. Thanks for any suggestions or help Tim.

6 years, 8 months

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

JackAudio March 2018