[PLUG] USB 3.x drivers

[Chuck Hast]

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 <techkoenig at gmail.com> 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 <
> freebsd at gndrsh.dnsmgr.net>
> wrote:
>
> > >
> > > > On Oct 23, 2019, at 11:05 AM, Rich Shepard <rshepard at appl-ecosys.com
> >
> > 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
> > rgrimes at freebsd.org
> > _______________________________________________
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> > PLUG at pdxlinux.org
> > http://lists.pdxlinux.org/mailman/listinfo/plug
> >
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-- 

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