2009/11/27 Clemens Ladisch <clemens@xxxxxxxxxx>: > Vladimir Komendantsky wrote: >> 2009/11/23 Clemens Ladisch <clemens@xxxxxxxxxx>: >> > Insufficient for what? MIDI and full duplex audio with 16 bits at >> > 44.1 kHz work fine with full speed. >> >> Not quite. Counterexamples include mp3 playback (16 bit / 44.1 KHz or >> less) from a computer to the audio interface (clicks and distorted >> sound after several seconds - probably a buffer overflow symptom - >> gets even worse after more time) and playing virtual instruments by >> sending MIDI to a software synthesizer like fluidsynth, with audio >> being sent back to the audio interface (clicks, delays, distortion). > > These problems are not related with bandwidth. > > To the same problems apprat when you connect the device to a computer > without the vendor drivers? Actually I haven't tried. I think they might because their possibility without the drivers was suggested in the manual. I've accidentally found that these symptoms do not appear in the 2.6.30 kernel that I've recompiled with pre-emptive RCU and "fixed endpoints" for my keyboard in usbquirks.h. Although the latter doesn't seem to make any difference because, without pre-emption, it alone does not suffice to improve audio quality. While, with pre-emptive RCU, the speed is still 12 Mb/s, audio works much better and the annoying clicks and other symptoms have disappeared. Regards, Vladimir -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
