Ralf Mardorf wrote: > David Olofson wrote: >> On Thursday 25 March 2010, at 13.32.43, David Olofson >> <[email protected]> wrote: >> >>> On Thursday 25 March 2010, at 12.49.31, Ralf Mardorf >>> <ralf.mard...@alice- >>> dsl.net> wrote: >>> [...] >>> >>> >>>> Btw. the >>>> graphics has access to the main memory, unfortunately it's a shared >>>> RAM, >>>> OTOH I used HPET so unwanted interrupts because of a shared RAM >>>> shouldn't be the cause, if I do understand the workings of HR timers >>>> correctly. >>>> >> [...interrupts, DMA etc...] >> >> BTW, the most common problem with graphics and realtime systems seems >> to be drivers abusing PCI port blocking as a performance hack. When >> the command buffer on the video card is full, the PCI bus blocks the >> CPU (completely - no IRQs, no nothing), instead of the driver going >> to sleep and waiting for an IRQ or some other proper solution. Might >> improve the 3D framerates slightly, but kills lowlatency audio... >> > > Mobo: M2A-VM HDMI > Graphics: ATI Radeon X1250-based graphics, *onboard* > Slot for another graphics is an PCI Express slot, no AGP etc. > > The HDMI card is demounted from the PCI Express slot and HDMI is > disabled by the BIOS. > I'm not using a proprietary 3D driver and I wasn't able to test one, > because it doesn't work using Linux, even though there is a 3D driver > for this card and Linux, perhaps the problem is "...-based". > > The USB MIDI interface is a 1 in and 1 out, very cheap swissonic. > > I suspect the graphics and the USB device causing to much MIDI jitter. > > I need to search for an old test, but have no time to do it right now, > but I do remember that Windows without HPET was better, than Linux > with HPET as sequencer timer source, while all other Linux sequencer > timer sources were much more out of time. > > Btw. I don't think that Windows would solve this issue for me, the > jitter for my current system is bad with both OSs. I know people where > Linux is bad and Windows does solve this issue ... perhaps Windows > will cause other issues for them ;).
My PCI Envey24 based card at least gives access to one of the Envy's MPUs, unfortunately I wasn't able to use the Terratec EWX 24/96 MPU. I tried different circuits using a BreadBoard. I won't buy a MIDI cable from Terratec ;). _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/listinfo/linux-audio-dev
