[linux-audio-dev] USB-MIDI Transfer rate
Jens M Andreasen
jens.andreasen at chello.se
Wed Sep 21 12:31:40 EDT 2005
On Wed, 2005-09-21 at 09:54 +0200, Clemens Ladisch wrote:
> It seems the usb-midi driver grabbed the device first. Disable it in
> the kernel configuration, or put the line
> into the /etc/hotplug/blacklist file.
Now to get back to the subject. By changing
ep->max_transfer = usb_maxpacket(umidi->chip->dev, pipe, 1);
in the snd_usbmidi_out_endpoint_create function in usbmidi.c to:
ep->max_transfer = 512;
.. I get a 16 fold increase in thruput.
Test data was a SysEx dump for upgrading the firmware which used take
~25 sec, now ~1.6 sec. The cute little LCD progress animation isn't
really visible anymore, but the update appears to be intact.
mvh // Jens M Andreasen
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