Re: usb issue

["George N. White III" <gnwiii@xxxxxxxxx>]

On Sat, 2 May 2020 at 09:16, George N. White III <gnwiii@xxxxxxxxx> wrote:

On Sat, 2 May 2020 at 00:13, ToddAndMargo via users <users@xxxxxxxxxxxxxxxxxxxxxxx> wrote:

Hi All,

I just installed
     Fedora-Xfce-Live-x86_64-32-1.6.iso

on a customer's old laptop.  The laptop previously had
Windows XP installed on it.  So many things had gone
wrong that it was time to  try something else.

Okay, the laptop now runs beautifully, with one exception.
If I copy files from a USB3 flash drive (all the ports
are USB2) the entire machine freezes: screen, mouse,
keyboard are completely frozen.
_storage 
Now I tortured the machine for hours with streaming
this and that, kpat, etc..  As long as I do not
insert a USB3 flash drive, the machine works perfectly.

May I presume that her USB2 ports are power
compromised?  Your thoughts.

Flash drives shouldn't use much power, but there could

be issues with power management on USB ports

and devices.   

Have you tried USB3 flash drives from multiple

vendors?

Can you boot a different distro from a live CD/DVD?

If you find one that works you can compare module 

versions and options (quirks).

Most systems seem to use usb_storage and uas

modules.

usb_storage has a quirks parameter.  With luck someone

with the same usb chipset has found the quirk setting

you need and put the details where Goggle can find 

them.

Sending the above jogged my memory:

https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=245931  

UAS is an upgraded transport protocol compared to USB mass-storage - commands and data are separated into different queues and multiple outstanding commands can be in flight at the same time, as opposed to USB mass-storage's lock-step relationship between commands and data. This allows better saturation of the 4GBps USB3.0 transport as there can be a continuous stream of data to and from a device.

It's very rare to see a UAS enabled USB2.0 device. Almost all USB3.0 devices on the market today are UAS-capable. It should be noted that if you plug a USB3.0 UAS device into a USB2.0 port on the Pi 4, the UAS driver will still be used - but at a slower top speed.

UAS is wonderful, until you come across UAS devices that don't fully implement the UAS specification. Typically, these devices will just stop responding when issued UAS commands that they don't like, or may in rare cases throw write data away which can cause filesystem corruption.

The Linux kernel has a built-in blacklist for devices known to be unreliable when using UAS. This is not an exhaustive list - if a manufacturer releases a new version of a controller with a different product ID, the blacklist will no longer match.

--

George N. White III

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