Re: usb disk drive disconnect making readonly

[Alan Stern <stern@rowland.harvard.edu>]

On Wed, May 04, 2022 at 09:16:55PM +0100, James Dutton wrote:
> Hi,
> 
> Use case:
> Boot from a USB disk and run for a day.
> Sometimes the USB link disconnects and reconnects.
> When it reconnects, Linux cannot use it, and the Linux kernel has set
> the device mount to read only.
> Is there any way to allow a USB disk to disconnect and then reconnect
> it, and Linux carry on using it, and not set it to a read-only mount,
> provided of course, that it knows that the same disk was reconnected
> without being changed.
> For example, I have a usb disk device that goes into power save mode
> if not accessed for more than 15 mins. When I come back to unlock the
> screensaver, it does not wake up the disk, but instead places it in
> read-only mode. This necessitates me to reboot the PC to get it
> working again.
> 
> Any ideas?

There is no way to know what is going on unless you provide a lot more 
information.  The dmesg log showing what happens during one of these 
disconnect/reconnect events would be a good start (although it probably 
won't be enough).

Alan Stern