31 Aug
2016
31 Aug
'16
9:22 a.m.
On 08/30/2016 11:47 PM, Len Ovens wrote:
On Tue, 30 Aug 2016, Greg wrote:
I can recommend this one, almost the same chipset:
http://www.dx.com/p/ake-007-2-port-usb-3-0-high-speed-pci-e-expansion-card-…
Used it with a RME Babyface and it performed way better than the onboard
USB ports. So I reckon the Newegg one will do a good job too.
I suspect the previous USB chipset was causing me
more problems than
typical,
as I am now very much enjoying the OOTB experience. I did see updates
to the
driver as well (workarounds/adding delays) in the time that had elapsed.
I am told that all motherboard chipsets are less than they could be.
Intel or VIA usb chipsets generate more interrupts than NEC (or maybe
SIS). The defining factor it seems is the USB 1.1 part of things. There
are two of them intel/via use the UHCI driver which expects the MB CPU
to do lots of the work. Other chips use the OHCI protocol which does as
much work as possible in the chipset. This one uses a NEC chipset but is
USB3 so I don't know what the control protion is:
http://www.newegg.ca/Product/Product.aspx?Item=9SIAA0D4C34273&cm_re=PCI…
For something more expensive that has OHCI in the spec:
http://www.newegg.ca/Product/Product.aspx?Item=N82E16815114048&cm_re=PC…
I do not know where things fall in the OHCI/UHCI with USB3 chipsets...
but I think we can be pretty sure Intel/VIA go the cheap way. Thing is,
even if USB3 doesn't use the O/UHCI part of things, almost all
multichannel USB audio interfaces do. It might be worth while having a
list of known good chipsets/PCIe USB cards.
BTW, even with uhci drivers, I found it made a big difference to:
a) make sure the irq that goes with that driver/usb port is not shared.
b) rtirq lists that usb port separately from the rest (IE. usb3 usb, not
just usb)
c) nothing else is plugged into that port via a bridge/hub whatever.
+1.
This meant for me (on my netbook) only using the USB port on the right
side, not using the second USB port on the right side... adding a hub to
the left side USB port for everything else (I was running from a USB
hard drive at the time). I was able to run the (USB 1.1) audio device
with jack at 64/2 with no xruns with this set up. (Atom single core at
1.6Ghz) Test duration being overnight so 6 to 8 hours. (cron turned off,
ht off(well told Linux only one core), CPU gov performance (also tried
userspace at 800MHz with success), setting rtirq RTIRQ_NAME_LIST="usb3
snd usb".
For someone who has done some real world testing:
http://crimeandtheforcesofevil.com/blog/2016/07/25/so-hey-usb-chipsets-tota…
Some people did bother:
https://www.forum.rme-audio.de/viewtopic.php?id=19940
Point seems to be, that those going portable who rely on onboard USB...
you may want to load linux onto a Mac which I am told will have good
chipset, or expect to have higher latency. This is ok for recording, not
for softsynth or effects. Otherwise add a new USB card.
I do not know if the UHCI and OHCI drivers can run side by side or if
the internal USB would have to be disabled.
That shouldn't be necessary.
Jeremy