That depends: Usb 3+ and USB 2 have separate wiring. So, they are independent and do not interfere. I'd imagine that USB host controllers have both usb 2 and USB 3 implementations cobbled together.
USB 2 and 1.1 together can degrade to 1.1 speed depending on if the hub has implemented Transaction translator. https://en.wikipedia.org/wiki/USB_hub#Transaction_translator I may be wrong, so double check everything I said before relying on my memory ... so many USB versions at this point. -T On Wed, Oct 30, 2019, 17:03 Chuck Hast <[email protected]> wrote: > Does USB still default to the slowest device on the network? It used to be > that way, but have > not kept up with it. If that is still so then you sure do not want a slow > device on your fast part > of the USB system. If not then disregard. > > On Thu, Oct 24, 2019 at 7:48 PM Ben Koenig <[email protected]> wrote: > > > Here's a fun excerpt from a comment in the Linux kernel. Line 513, > xhci.c: > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/drivers/usb/host/xhci.c?h=v5.3.7 > > /* > > * Quirk to work around issue generated by the SN65LVPE502CP USB3.0 > > re-driver > > * that causes ports behind that hardware to enter compliance mode > > sometimes. > > * The quirk creates a timer that polls every 2 seconds the link state of > > * each host controller's port and recovers it by issuing a Warm reset > > * if Compliance mode is detected, otherwise the port will become "dead" > > (no > > * device connections or disconnections will be detected anymore). > Becasue > > no > > * status event is generated when entering compliance mode (per xhci > spec), > > * this quirk is needed on systems that have the failing hardware > > installed. > > */ > > > > Compatibility issues tend to occur in the implementation of the standard, > > not the standard itself. Since there are so many different USB versions, > > there are compatibility problems to match. And don't even get me started > on > > USB whitelisting. Apple rules their 'perfect system' with an iron fist. > > > > On Thu, Oct 24, 2019 at 11:57 AM Rodney W. Grimes < > > [email protected]> > > wrote: > > > > > > > > > > > On Oct 23, 2019, at 11:05 AM, Rich Shepard < > [email protected] > > > > > > wrote: > > > > > > > > > > ?The Asus Prime X470 motherboard in my desktop has several USB > ports. > > > It has > > > > > AMD Ryzen 2nd Generation ... > > > > > 4 x USB 3.1 Gen 1 (up to 5Gbps) ports at back panel (blue), > > > > > > > > > > AMD X470 chipset > > > > > - 1 x USB 3.1 Gen 2 (up to 10Gbps) front panel connector > > > > > - 2 x USB 3.1 Gen 1 (up to 5Gbps) ports at mid-board > > > > > - 2 x USB 3.1 Gen 1 (up to 5Gbps) ports at back panel (1 x Type-A > and > > > 1 x Type C) > > > > > - 4 x USB 2.0 ports at mid-board > > > > > > > > > > ASMedia USB 3.1 controller > > > > > - 2 x USB 3.1 Gen 2 (up to 10Gbps) ports at back panel (teal blue) > > > > > > > > > > I want to understand how all these differ and which to use for > what. > > > > > Pointers > > > > ... > > > > > > > > Rich > > > > > > > > In general, if the plug fits you can plug in anything anywhere. > > Usually > > > it?ll run just fine. Higher speed ports are generally backward > > compatible, > > > and most older slow devices will work in a faster port. Now the key is > > > SPEED. It makes no sense to plug a keyboard or mouse ( usually USB 1.1 > > or > > > 2) into a usb 3.x port. you should match the external Device speed > with > > > the port. Why plug a usb 3.1 gen 2 external hard drive into usb 2? > > > > > > > > It?s just that simple. Not rocket science. > > > > > > Until it isnt that simple. I have seen cases of USB 3.x flash drives > > > that actually wont work in a 3.x plug, but work fine in a USB 2.x > > > plug. This is usally on early generation 3.0 systems using a late > > > generation 3.1 USB device. > > > > > > YMMV, be aware, not all things are as compatible as the standards > > > say they should be! > > > > > > > -Ed > > > > > > -- > > > Rod Grimes > > > [email protected] > > > _______________________________________________ > > > PLUG mailing list > > > [email protected] > > > http://lists.pdxlinux.org/mailman/listinfo/plug > > > > > _______________________________________________ > > PLUG mailing list > > [email protected] > > http://lists.pdxlinux.org/mailman/listinfo/plug > > > > > -- > > Chuck Hast -- KP4DJT -- > I can do all things through Christ which strengtheneth me. > Ph 4:13 KJV > Todo lo puedo en Cristo que me fortalece. > Fil 4:13 RVR1960 > _______________________________________________ > PLUG mailing list > [email protected] > http://lists.pdxlinux.org/mailman/listinfo/plug > _______________________________________________ PLUG mailing list [email protected] http://lists.pdxlinux.org/mailman/listinfo/plug
