Re: [LAU] kernel changes

On Sun, 2013-02-10 at 10:09 -0800, Len Ovens wrote:
> On Sun, February 10, 2013 9:37 am, Ralf Mardorf wrote:
> > On Sun, 2013-02-10 at 09:25 -0800, Len Ovens wrote:
> >> What I am says though is that I'm not sure these problems are kernel
> >> problems. They may be kernel module problems or something else. I have
> >> used all of these kernel versions and been able to run low latency on
> >> all
> >> of them no problems (ICE1712 based card). Other people on this list have
> >> had no problems too. Yet there is not just one person with this same
> >> problem. We (on this list) might do well to explore the differences
> >> between our hardware/software to see if we can find the problem.
> >
> > Hi Len :)
> >
> > regarding to latency and xruns _on my machine_ two cheap ICE1712 PCI
> > cards are working better on Linux, than my RME PCI express card. Tested
> > with kernels from 2.6.29 full preempt on Debian to
>
> I am wondering if PCIe or it's drivers may be a problem for low latency.
> Having read a little about the standard, it would seem that the earliest
> standards (v1) are better for low latency than later (v4) standards. The
> improvements have been in throughput at the expense of latency. I wonder
> if it is possible to have a PCIe slot set to a particular version of the
> PCIe standard. Or to do so at the card end. As a distro assembly
> volunteer, I can only test things with the HW I have, which is older (no
> PCIe slots at all). What I have read about the RME PCIe products is that
> they are native PCIe rather than bridged PCI to PCIe.
>
> I wish I had the funding to test full time and buy a better representation
> of the HW out there, but I don't.

"HDSPe AIO is the newly developed PCI Express version of the HDSP 9632.
A newly developed genuine PCI Express core consequently takes full
advantage of the new format, achieving significant performance gains in
multitrack audio and lowest latency. Thanks to RME's secure flash update
technology, firmware improvements, adjustments, and bugfixes can be
installed easily at any time." -
http://www.rme-audio.de/en_products_hdspe_aio.php

For this card the Linux driver is very limited and I never updated the
firmware, so also possible is, that

- perhaps newer firmware is needed
- perhaps a better Linux driver is needed
- perhaps PCI on my mobo is good, but PCI express on the same mobo is
  bad

*?*

Regards,
Ralf

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Received on Sun Feb 10 20:15:18 2013