Re: [LAD] Optimized device driver to Fast Track Pro (start developing)
On 23/11/2012 20:01, rodr...@angoera.com.br wrote: Hi ! The Fast Track Pro is USB 1.0, the max bandwidth is 12Mb/s. The TUSB3200 has the isochronous USB transfer mode, that can occupy about 90% of the USB bandwidth... Using 4 channel (2 IN and 2 OUT) with right and left, and 24 bits (3 bytes each, in total 4(channel) * 2(left,right) * 3(data) = 24 bytes ) The max bandwidth that could communicate is about 12Mbits/s = 1.5 Mbytes/s | 1.5 Mbytes/s * 0.9 = 1.2 MBytes/s -- 1.2MBytes/s / 24 bytes = 50Khz ... So the maximum USB 1.0 with 24 bits is 4 chanel in 48KHz... You're absolutely right, the 24 bits 4 channels mode would be only accessible in 48 kHz samplerate. I would like to know how it works the interface between USB AUDIO CLASS device driver and the USB-AUDIO Alsa Device driver. And how does the isochronous comunication works inside the kernel? Because I am using an RT Kernel and I would like to set with the high priority this communication. I don't really know how does the isochronous, but applying usual RT security audio rules seems sufficient to get high priority access and then very low latency (got 3 ms here with few audio realtime processes..). Further info here: http://joegiampaoli.blogspot.fr/2011/06/m-audio-fast-track-pro-for-debian-linux.html G ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Optimized device driver to Fast Track Pro (start developing)
On Thu, 22 Nov 2012 08:42:20 -0500, Paul Davis wrote: On Thu, Nov 22, 2012 at 7:44 AM, wrote: Hi every body, I would like to develop an very optimized device driver for the USB soundcard, I am going to use the IC TUSB3200 similar the Fast Track Pro from M-Audio (I would like to optimize this device driver as well) , I am a hardware developer, and now I gonna start in the Linux world... I would like to know if someone could tell me what the better path to learn and develop an USB sound card??? if this is a class compliant device, then there is already a driver for it and any work you do to get things working should focus on just making sure that the existing ALSA driver works with whatever quirks the device may have. if it not a class compliant device, why not? I am developing an audio processing product that will have this specific sound card, so I need to be sure that I have be best performance, maybe the class compliant device is enough, but I would like to know the audio path since the hardware until the application and I have time to make it better and collaborate for the community. Links: -- [1] mailto:rodr...@angoera.com.br ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Optimized device driver to Fast Track Pro (start developing)
2012/11/22 rodr...@angoera.com.br: I would like to develop an very optimized device driver for the USB soundcard, I am going to use the IC TUSB3200 Some resources - http://www.alsa-project.org/main/index.php/Developer_Zone http://kernel.org/doc/htmldocs/writing-an-alsa-driver.html http://kernelnewbies.org/Drivers http://www.freesoftwaremagazine.com/articles/drivers_linux http://www.linuxjournal.com/article/7353 http://www.linuxjournal.com/article/4786 -- E.R. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Optimized device driver to Fast Track Pro (start developing)
On 22/11/2012 17:27, rodr...@angoera.com.br wrote: On Thu, 22 Nov 2012 08:42:20 -0500, Paul Davis wrote: On Thu, Nov 22, 2012 at 7:44 AM, wrote: Hi every body, I would like to develop an very optimized device driver for the USB soundcard, I am going to use the IC TUSB3200 similar the Fast Track Pro from M-Audio (I would like to optimize this device driver as well) , I am a hardware developer, and now I gonna start in the Linux world... I would like to know if someone could tell me what the better path to learn and develop an USB sound card??? if this is a class compliant device, then there is already a driver for it and any work you do to get things working should focus on just making sure that the existing ALSA driver works with whatever quirks the device may have. if it not a class compliant device, why not? I am developing an audio processing product that will have this specific sound card, so I need to be sure that I have be best performance, maybe the class compliant device is enough, but I would like to know the audio path since the hardware until the application and I have time to make it better and collaborate for the community. Hi! I'm the author of the driver included in the kernel from 3.1: http://git.kernel.org/?p=linux/kernel/git/tiwai/sound.git;a=commitdiff;h=0f5733b0c883158b13366ae34b5e4bd52a1ac346 an example of the modprobe conf files: http://files.parisson.com/debian/fast-track-pro.conf As Paul said, this device is indeed class compliant so it can works in stereo 16 bits mode on any kernel version.. But, to get its special features (24 bits mode, spdif, etc..), we need some quirks provided by my patch. But, I know the current driver is not perfect, mainly because we can't get the 4 output channels working.. So you are welcome to participate and improve it! I can just strongly advise you to start from the current state of the driver so that the maintainer of the alsa part (Takashi Iwai) can merge it properly.. Cheers, G ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
