Diagnose why usb3 and /boot flash is failing to mount sporadically

Discussion in 'all things UNIX' started by Palancar, May 6, 2016.

  1. Palancar

    Palancar Registered Member

    Joined:
    Oct 26, 2011
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    1,594
    Not sure if I am entering a physically tired motherboard scenario, OR if something else is going on. Brief description of issue:

    I have a laptop with usb3 ports and a usb2 port. I am running Debian and using flash drives for my /boot, with nothing on the drive unencrypted for linux. 50% of the time my linux OS's (several with different systems on different partitions using different flash devices) will mount perfectly and smoothly. The other half of the time my machine doesn't seem to see the /boot sticks when inserted in a usb3 slot prior to boot. Obviously during those times I cannot boot linux without it seeing /boot. When I move the /boot stick to a usb2 slot it ALWAYS opens without a hitch of any kind.

    I am looking for suggestions as to how to diagnose this issue and resolve it if possible with reasonable effort. When the system is mounted I have tried to update grub and then do a fresh install of grub in case something is off in the flash. I haven't checked as to whether there is a newer bios "flash" for this machine and that would be last resort - trying to avoid a possible brick.

    The confusing issue is that it works 50% of the time and fails 50% of the time. What gives?

    Would appreciate any ideas on the subject. I only have one usb2 port so I am wary of wearing it out as opposed to 3 usb3 ports.
     
  2. Mrkvonic

    Mrkvonic Linux Systems Expert

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    8,698
    What do you see in the system log (syslog) and dmesg when you plug in these devices and they mount successfully - and then not?
    Mrk
     
  3. MsFluffyMuffin

    MsFluffyMuffin Registered Member

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    Location:
    UK
    Sadly this is down to the deferred initialisation of USB 3.x during POST and booting of the OS to speed up the POST and boot process so your computer boots to the OS faster, in many cases it only makes it 1-3 seconds faster but causes all kinds of issues like yours, you are not alone as I have same issue as well, the only alternative is to use a USB 1.x or USB 2.0 port as these are still initialised earlier on, alot of people have suffered with keyboards and mice failing to work when the OS has loaded, they had to use a USB 2.0 port which is often recommend by manufacturers as they are aware of the problem with these USB 3.x initialisation failures :eek:(
     
  4. Palancar

    Palancar Registered Member

    Joined:
    Oct 26, 2011
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    Actually this is what I expected, but was hoping for a "solvable" way to go. I have never had a usb slot wear out but using my only usb2 slot with 3 usb3 slots sitting here is not comforting. As expected all the slots are fine once I am mounted.


    This scenario seems to have started in aggregate in the last month or so, which is why I thought maybe Debian had updated something that may be causing this.



    I will check my syslog when I get home.
     
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