Mark Knecht wrote: > On Thu, 2004-01-22 at 07:12, Clemens Ladisch wrote: > > (I've added this to my TODO list (which doesn't mean anything).) > > It means you are organized enough to have a TODO list. That's good.
Now if I remembered where I've put my TODO list ... ;-) > One other related frustration about Alsa MIDI is that under Gentoo at > least my MidiSport is never recognized by Alsa until I hotplug it. Is it recognized when you run "modprobe snd-usb-audio"? Is there a snd-usb-audio entry in your modules.conf? > > > 3) I have undocumented low-level 'concerns' about the timing accuracy of > > > MIDI under Linux, but it's not so bad as to warrant 'worry' or a bug > > > report. Just concerns that there is more jitter in my Linux MIDI created > > > audio than on my Windows boxes. > > > > What timer are you using for the sequencer? The default system timer > > on 2.4.x has a resolution of 100 Hz. I'm using the timer on my ymfpci > > card with 1000 Hz. (Yeah, completetely undocumented, that one, like > > the RTC timer. (TODO: FAQ #15)) > > This answer confuses me. Do I need to do something with both 'timers' > AND 'the RTC to make Alsa work better? The sequencer needs some high-resolution interrupt source to deliver events accurately. By default, it uses the Linux system timer, which runs with 100 Hz on 2.4 (but 1000 Hz on 2.6) kernels. A standard Linux system does not have any other available timer. There exists a patch for 2.4 kernels which allows to use the RTC interrupt (with 1024 Hz). (It's in alsa-driver/utils/patches/, but it doesn't apply cleanly to the latest 2.4.x kernels. (another TODO)) YMFPCI cards have a timer which can be used for this, too. > Is fixing/improving this done by changing the 'Timer Frequency' in > the General Setup section of menuconfig, or is this some setting > on the sound card itself? If your system has another timer (a standard system has not), it can be reconfigured with module parameters for snd-seq. See /proc/asound/timers for a list of timers (but please note that PCM timers won't help you). Regards, Clemens ------------------------------------------------------- The SF.Net email is sponsored by EclipseCon 2004 Premiere Conference on Open Tools Development and Integration See the breadth of Eclipse activity. February 3-5 in Anaheim, CA. http://www.eclipsecon.org/osdn _______________________________________________ Alsa-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-user
