Re: [LAD] Tascam US-16x08 0644:8047

On 08/30/2016 11:47 PM, Len Ovens wrote:
> On Tue, 30 Aug 2016, Greg wrote:
>
>> 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=PCIe_USB_card-_-9SIAA0D4C34273-_-Product

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-for-desktop-blue-silver-208899

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.

>
> For something more expensive that has OHCI in the spec:
> http://www.newegg.ca/Product/Product.aspx?Item=N82E16815114048&cm_re=PCIe_USB2_card-_-15-114-048-_-Product
>
> 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-totally-matter/

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

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