[LAD] MIDI jitter - was: automation on Linux (modular approach)

[David Olofson]

On Thursday 25 March 2010, at 14.55.41, Ralf Mardorf <ralf.mardorf at alice-
dsl.net> wrote:
[...]
> Mobo: M2A-VM HDMI
> Graphics: ATI Radeon X1250-based graphics, *onboard*
> Slot for another graphics is an PCI Express slot, no AGP etc.
[...]

Have you disabled all BIOS and other power management, CPU clock throttling 
etc?

Are you using fbdev (VESA graphics) or similar, or are you using the 
"hardware" text mode console? The latter can cause trouble with some 
integrated graphics solutions, that don't actually *have* text modes, but 
emulate then through BIOS super-NMIs. This can block any normal IRQs for tens 
or even hundreds of milliseconds! I doubt a desktop oriented motherboard with 
ATI or nVidia graphics would have this problem, but you never know.


> I suspect the graphics and the USB device causing to much MIDI jitter.
[...]

Have you tested it with another "known working" computer? Could be an issue 
with the driver or the hardware...

Also, are there any other USB devices connected to the same hub? (Integrated 
or external.) Are other devices sharing IRQ with the USB hub the MIDI 
interface is connected to?


-- 
//David Olofson - Developer, Artist, Open Source Advocate

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