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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