Re: high speed data to usb disk makes the kernel think that is has been unmounted

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Aug 11, 2020 at 08:34:53PM +0200, Patrik Nilsson wrote:
> Hi Greg,
> > Can you provide kernel logs?  Odds are the disk disconnects itself as it
> > takes too much power or something.
> udev-kernel logs can be found:
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1886172

udev logs do not help, can you do, from a command line:
	sudo dmesg -c		# clears the kernel log
	<do your testing>
	dmesg > kernel_log.txt

and send us the kernel_log.txt file?

> I have tested the usb to sata adapter directly connected to a computer and
> connected to a externally powered usb hub. The bug behavior is the same.

I bet the adapter can't handle the issue here, writing a lot of data to
flash does take a lot of power.

> One time when I tested the whole usb hub disconnected. I have a usb to
> ethernet connected to it too. It vanished and appeared again. Doubt it is
> power. The externally powered hub can deliver 4A, but I hope the usb to sata
> only takes 2A.

If the whole hub disconnected, that is a _huge_ hint it's a power issue,
the operating system can not do that on its own.

thanks,

greg k-h