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#1 2024-10-23 11:25:09

archuser_9999
Member
Registered: 2019-08-17
Posts: 88

[SOLVED] USB ports, front panel vs rear - any differences?

Got to this perhaps odd question via struggling to make backups. For context:

a nearly new Seagate 1Tb USB HDD. Having reinstalled Arch/i3 from scratch, time for my first backup using Grsync.

I've been using either of the two front panel USB ports - one is USB.2.0 the other is USB.3.0. However, for reasons of perhaps age/wear or something else... suddenly I'm beset with all manner of I/O errors while both using Grsync and while attempting to mount/unmount/safely remove the disk from Thunar (I have volman etc). I looked in dmesg too, seeing all sorts of handles being closed, or things timing out.

It led me to endless amounts of error checking the disk, removing labels and reformatting etc. but, finally I plugged it into the rear USB.3.0 port that's connected to the mainboard, and everything went swimmingly - not a single I/O error nor any issues mounting/unmounting.

So while I now know to use this port in future, it got me wondering about whether there are any material differences between these two sets of ports, or any differences in the way they may be handled within Linux.

Can one upgrade such things perhaps - with better connector cable, higher quality ports? The toll the disk takes when continually being interrupted would suggest it will wear out much faster. However, integrity of the backups is what matters most, and although I now will use this same port for future transfers...

Or maybe this 2015? motherboard is too old?

Last edited by archuser_9999 (2024-10-26 13:37:29)

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#2 2024-10-23 11:58:08

BS86
Member
Registered: 2022-11-03
Posts: 33

Re: [SOLVED] USB ports, front panel vs rear - any differences?

front USB usually is connected to the Motherboard via cable and connectors. Rear USB are soldered. That alone makes a huge difference.

In addition, front panel USB ports can have significantly less build quality compared to motherboard ports - the can is important, it can also be the opposite.
Depending on individual hardware-skills, everything can be replaced, it depends on what you can do and how your tower is contructed. It can be a plug and play replacement or need several tools and soldering.

Last edited by BS86 (2024-10-23 11:58:42)

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#3 2024-10-23 12:21:06

archuser_9999
Member
Registered: 2019-08-17
Posts: 88

Re: [SOLVED] USB ports, front panel vs rear - any differences?

okay thank you - that's helpful.

I can manage the DIY aspect, so I take it you're suggesting I can look up replacement parts on a suitable vendor, and swap them out?

Do you happen to know if things like voltage regulation or such might be treated differently between the two? Or does Linux just manage all this with nothing to be user set or checked/configured?

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#4 2024-10-23 12:54:37

BS86
Member
Registered: 2022-11-03
Posts: 33

Re: [SOLVED] USB ports, front panel vs rear - any differences?

from the OS perspective, they should be identical, as long as both are controlled by the same USB controller on the motherboard (most motherboards I know have 2 USB controllers, most of the time splitting USB 2 from 3 or 2/3 from 3.1/3.2 so you might need to check your motherboard documentation for that.

For the replacement, more or less yes, almost every company uses standard components that are available on the free market, too.
Before going that way, you can check for visible damage or dust deposit in the actual port.

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#5 2024-10-23 13:00:55

archuser_9999
Member
Registered: 2019-08-17
Posts: 88

Re: [SOLVED] USB ports, front panel vs rear - any differences?

BS86 wrote:

For the replacement, more or less yes, almost every company uses standard components that are available on the free market, too.
Before going that way, you can check for visible damage or dust deposit in the actual port.

yes, good idea! I have also thought of a simpler solution too... which is to purchase a USB 'hub' or expander, connect it to the rear USB port, and simply ignore the front ports altogether. One of these days I'm going to upgrade this entire thing, and possibly go with an NUC, so these issues will eventually disappear of their own accord.

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#6 2024-10-23 13:46:02

ewaller
Administrator
From: Pasadena, CA
Registered: 2009-07-13
Posts: 20,179

Re: [SOLVED] USB ports, front panel vs rear - any differences?

Is it a spinning drive? How much DC current @ 5VDC  does the drive pull from the port?  If it is a high number, all other things being equal, you could also be experiencing a voltage drop on the internal cables caused by extra connectors and longer cable runs.  At an amp, you could loose half a Volt if there were half an Ohm of extra resistance.   Things might get dicey if things get down around 4.5V.

Do other devices that have more conservative power requirements have errors?   
Have you read your Journal output?  Any mentions of over current on the ports? Connects, disconnects?  Or just I/O errors?


Nothing is too wonderful to be true, if it be consistent with the laws of nature -- Michael Faraday
Sometimes it is the people no one can imagine anything of who do the things no one can imagine. -- Alan Turing
---
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#7 2024-10-23 13:52:08

archuser_9999
Member
Registered: 2019-08-17
Posts: 88

Re: [SOLVED] USB ports, front panel vs rear - any differences?

ewaller wrote:

Is it a spinning drive? How much DC current @ 5VDC  does the drive pull from the port?  If it is a high number, all other things being equal, you could also be experiencing a voltage drop on the internal cables caused by extra connectors and longer cable runs.  At an amp, you could loose half a Volt if there were half an Ohm of extra resistance.   Things might get dicey if things get down around 4.5V.

Do other devices that have more conservative power requirements have errors?   
Have you read your Journal output?  Any mentions of over current on the ports? Connects, disconnects?  Or just I/O errors?

It is yes.

Very good questions which, as yet, I've not investigated far. Some instinct had told me that my I/O errors may indeed have been caused by voltage irregularity from the USB port, although I've not attempted to measure anything. Dmesg output didn't mention voltages as such - understandably perhaps I'm not keen to now deliberately recreate the issue just to look further. Dmesg showed connect/disconnect errors, and the thunar notifyd was telling me "unable to ... I/O error".

I will look at the UEFI settings on my board, in case there's some sort of option for "overclocking" USB ports. AFAIK I don't have this kind of issue if I plug in a USB thumb drive - they always seem to work. True that this relates to a 2.5" SATA disk in a USB enclosure.

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#8 2024-10-23 14:39:04

subwaypassenger
Member
Registered: 2017-04-18
Posts: 10

Re: [SOLVED] USB ports, front panel vs rear - any differences?

What are your power settings?

grep . /sys/class/scsi_host/host*/link_power_management_policy

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#9 2024-10-23 14:42:27

archuser_9999
Member
Registered: 2019-08-17
Posts: 88

Re: [SOLVED] USB ports, front panel vs rear - any differences?

subwaypassenger wrote:

What are your power settings?

grep . /sys/class/scsi_host/host*/link_power_management_policy

grep . /sys/class/scsi_host/host*/link_power_management_policy
/sys/class/scsi_host/host0/link_power_management_policy:med_power_with_dipm
/sys/class/scsi_host/host1/link_power_management_policy:med_power_with_dipm
/sys/class/scsi_host/host2/link_power_management_policy:med_power_with_dipm
/sys/class/scsi_host/host3/link_power_management_policy:med_power_with_dipm
/sys/class/scsi_host/host4/link_power_management_policy:med_power_with_dipm
/sys/class/scsi_host/host5/link_power_management_policy:med_power_with_dipm

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#10 2024-10-26 13:38:42

archuser_9999
Member
Registered: 2019-08-17
Posts: 88

Re: [SOLVED] USB ports, front panel vs rear - any differences?

happy to mark as solved simply because

a) it was a rather general question with perhaps no specific answer(s)
b) can confirm that exclusive use of the "on board" USB port results in no errors

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