I have a problem with a USB 3 port on a desktop running Debian Linux. The problem started when a system backup was attempted to a portable hard drive plugged into the USB 3 port. The backup operation had previously been done many times with no problems.

This time the mount operation failed with a message of the type 'can't find UUID=....'

Various commands such as fdisk -l showed that the kernel was not detecting the drive.

The drive was unplugged, then replug with a dmesg command issued straight after the replug.
The dmesg output seemed to indicate the portable hard drive itself had some problem.

A new portable hard drive was plugged into the port, but the kernel could not see the new drive, although a slowly flashing light on the drive indicated some power was reaching the hard drive.

I thought that perhaps the port was not supplying enough power to the drive, so I then plugged a new USB flash drive into the port. However the kernel would not recognise the flash drive.

Someone subsequently suggested that perhaps the power pins of the port were working but not the data pins.
This could perhaps be due to a problem with the port's USB header or associated cabling or possibly due to damage to
the host controller or associated wiring.

Any thoughts on this, please.

The way to do dmesg thing is 'dmesg |tail after 10 seconds, which usua tells you the struggles it, been having.

Cables. Have you changed them?

Are you sure that the usb port on the machine isn't getting a little wollowed out. They do that. (wollowed is word, really)
Yup, look at the usb port. Unplug the drive.
Then plug the drive in, see if it comes ready, or if it continues to scroll info. Mess with the plug. Sometimes lightly plugging the usb cable in will work. Or pulling the plug back out very slightly.

A new portable hard drive and a new flash drive have each, in turn, been plugged into the same USB 3 port.
Neither of them have been recognised by the Debian kernel.

There are 4 USB buses - 3 have USB 2 root hubs while the other has a USB 3 root hub.

The kernel recognises 5 USB devices (mouse, old flash drive, card reader, printer, scanner),
which are each connected to the same USB 2 root hub.

The question is why are the new hard drive and new flash drive not being recognised by the kernel.

Is it a hardware problem with the USB 3 port or could it possibly a software problem ?

Which is more likely and what tests (both hardware and software) can be done, apart from the usual dmesg, fdisk, lsusb, lsblk, blkid checks ?

One or two people have mentioned turning off the computer completely (I.e. at the mains), waiting for a few minutes and then rebooting. I am hesitant to do this because the exact cause of the USB 3 port problem is not known and there is thus a possibility that the computer will not reboot.

Is the xhci module loaded? That's the obvious one.

Yes, xhci is installed.

The USB 3 port had been working okay, being regularly used to do a system backup
to a portable hard drive until one day when that drive could not be mounted :-
a 'can't find UUID=' type message being received instead. So it appears that the kernel
suddenly failed to recognise the drive.

From then onwards, the kernel has failed to recognise a new portable hard drive or
a new flash drive when these have been plugged into that USB 3 port.

After replying to your thread over here?

https://www.bleepingcomputer.com/for...al-hard-drive/

Have you tried a kernel change yet.

post

dmesg should say something also. Is this external drive seen by anything else? Windows/Mac/Chromebook?

I have now seen a number of cases where USB devices are not detected.

It seems that the xhci_hcd driver needs to be replaced/reinitialised.

Some of the posts recommend that the computer is completely powered down (I.e. all external devices are unmounted,the computer is switched off and unplugged from the mains). After a wait of, say, up to 30 minutes, the computer is rebooted. The xhci_hcd driver should be reinitialised by the reboot, so the USB 3 port should then work fine.

Other posts suggest that instead of a power down and reboot, the xhci_hcd driver could be disabled and then re-enabled similar to suggestion in https://zedt.eu/tech/linux/restartin...system-centos/

Does anyone know which directory contains the xhci_hcd driver in Debian, please ?

I don't know exactly which directory is the xhci_hcd you need, but try this I don't see how that's much use, as it is loaded in ram. Wherever it is, you can remove & install it with

The new flash drive was unplugged from the USB 3 port.

As root, the following command was run

dmesg* |* tail


The output was :

[3974120.938338] usb 1-1: new high-speed USB device number 66 using xhci_hcd
[3974126.430777] usb 1-1: new high-speed USB device number 67 using xhci_hcd
[3974131.923271] usb 1-1: new high-speed USB device number 68 using xhci_hcd
[3974137.415713] usb 1-1: new high-speed USB device number 69 using xhci_hcd
[3974142.908184] usb 1-1: new high-speed USB device number 70 using xhci_hcd
[3974148.400664] usb 1-1: new high-speed USB device number 71 using xhci_hcd
[3974153.893132] usb 1-1: new high-speed USB device number 72 using xhci_hcd
[3974159.385762] usb 1-1: new high-speed USB device number 73 using xhci_hcd
[3974164.878067] usb 1-1: new high-speed USB device number 74 using xhci_hcd
[3974170.370558] usb 1-1: new high-speed USB device number 75 using xhci_hcd


Then the new flash drive was plugged back into the USB 3 port and then, again as root,
the following command was run

dmesg | tail -50

The output was as follows :

[3973945.175272] usb 1-1: new high-speed USB device number 34 using xhci_hcd
[3973950.667736] usb 1-1: new high-speed USB device number 35 using xhci_hcd
[3973956.164234] usb 1-1: new high-speed USB device number 36 using xhci_hcd
[3973961.660705] usb 1-1: new high-speed USB device number 37 using xhci_hcd
[3973967.153175] usb 1-1: new high-speed USB device number 38 using xhci_hcd
[3973972.645644] usb 1-1: new high-speed USB device number 39 using xhci_hcd
[3973978.138108] usb 1-1: new high-speed USB device number 40 using xhci_hcd
[3973983.630571] usb 1-1: new high-speed USB device number 41 using xhci_hcd
[3973989.123038] usb 1-1: new high-speed USB device number 42 using xhci_hcd
[3973994.615532] usb 1-1: new high-speed USB device number 43 using xhci_hcd
[3974000.107987] usb 1-1: new high-speed USB device number 44 using xhci_hcd
[3974005.600444] usb 1-1: new high-speed USB device number 45 using xhci_hcd
[3974011.092914] usb 1-1: new high-speed USB device number 46 using xhci_hcd
[3974016.586439] usb 1-1: new high-speed USB device number 47 using xhci_hcd
[3974022.069876] usb 1-1: new high-speed USB device number 48 using xhci_hcd
[3974027.562378] usb 1-1: new high-speed USB device number 49 using xhci_hcd
[3974033.054785] usb 1-1: new high-speed USB device number 50 using xhci_hcd
[3974038.547262] usb 1-1: new high-speed USB device number 51 using xhci_hcd
[3974044.039723] usb 1-1: new high-speed USB device number 52 using xhci_hcd
[3974049.532213] usb 1-1: new high-speed USB device number 53 using xhci_hcd
[3974055.024682] usb 1-1: new high-speed USB device number 54 using xhci_hcd
[3974060.517132] usb 1-1: new high-speed USB device number 55 using xhci_hcd
[3974066.013620] usb 1-1: new high-speed USB device number 56 using xhci_hcd
[3974071.506102] usb 1-1: new high-speed USB device number 57 using xhci_hcd
[3974076.998569] usb 1-1: new high-speed USB device number 58 using xhci_hcd
[3974082.491021] usb 1-1: new high-speed USB device number 59 using xhci_hcd
[3974087.983486] usb 1-1: new high-speed USB device number 60 using xhci_hcd
[3974093.475956] usb 1-1: new high-speed USB device number 61 using xhci_hcd
[3974098.968439] usb 1-1: new high-speed USB device number 62 using xhci_hcd
[3974104.460916] usb 1-1: new high-speed USB device number 63 using xhci_hcd
[3974109.953390] usb 1-1: new high-speed USB device number 64 using xhci_hcd
[3974115.445836] usb 1-1: new high-speed USB device number 65 using xhci_hcd
[3974120.938338] usb 1-1: new high-speed USB device number 66 using xhci_hcd
[3974126.430777] usb 1-1: new high-speed USB device number 67 using xhci_hcd
[3974131.923271] usb 1-1: new high-speed USB device number 68 using xhci_hcd
[3974137.415713] usb 1-1: new high-speed USB device number 69 using xhci_hcd
[3974142.908184] usb 1-1: new high-speed USB device number 70 using xhci_hcd
[3974148.400664] usb 1-1: new high-speed USB device number 71 using xhci_hcd
[3974153.893132] usb 1-1: new high-speed USB device number 72 using xhci_hcd
[3974159.385762] usb 1-1: new high-speed USB device number 73 using xhci_hcd
[3974164.878067] usb 1-1: new high-speed USB device number 74 using xhci_hcd
[3974170.370558] usb 1-1: new high-speed USB device number 75 using xhci_hcd
[3974189.313961] usb 1-1: new high-speed USB device number 76 using xhci_hcd
[3974194.806428] usb 1-1: new high-speed USB device number 77 using xhci_hcd
[3974200.298916] usb 1-1: new high-speed USB device number 78 using xhci_hcd
[3974205.791363] usb 1-1: new high-speed USB device number 79 using xhci_hcd
[3974211.283830] usb 1-1: new high-speed USB device number 80 using xhci_hcd
[3974216.776300] usb 1-1: new high-speed USB device number 81 using xhci_hcd
[3974222.268794] usb 1-1: new high-speed USB device number 82 using xhci_hcd
[3974227.761269] usb 1-1: new high-speed USB device number 83 using xhci_hcd

Something is going wrong here.

That suggests to me a hardware issue. But I wouldn't bet the rent money on it.

Could the problem with the USB port possibly cause a problem if an attempt is made to reboot the system ?

Sounds like a hardware issue.

# lsblk

$ cat /proc/partition

lsblk should show the UUID if if if if...

If the drive is partitioned, the partitions should show up in /proc/partitions. I have some quirky drives that require a powered usb hub to work. Laptops usb ports are notoriously under powered. I have two of those drives and each requires their OWN usb powered hub to work. Although once that condition is met they work fine on a raspberry pi as a ZFS mirrored pair.

I am still struggling to solve the problem with the malfunctioning USB 3 port on a desktop
running Debian.

I would be very grateful if someone could please give useful answers to the following questions :-

(1) Can the desktop be safely rebooted, if needed, given the USB 3 problem?

(2) Can the USB 3 problem be fixed in some way or is the port now permanently
unavailable?

(3) If the USB 3 port is unavailable, can the new portable hard drive be used to
do a back-up of the system from the USB 2 port currently occupied by a card reader
or is there any risk the card reader will be messed up again afterwards ?

(On a previous occasion, a portable hard drive was plugged into this USB 2 port
in place of the card reader. The system issued a message indicating the port was busy.
The card reader was plugged back into the USB 2 port and it was then found that
a card inserted into the card reader could not be mounted).

hardware solutions I guess. Plug a usb2 hub into the usb3 port. Or a usb extension cable that is only usb 2.