这是三星Galaxy Tab A，我的电脑在Ubuntu上。
I cannot access data on my tablet by USB, because when I plug it in, it keeps popping a dialog to allow access, when I pick allow, the dialog pops up again, and so on endlessly.
This is a Samsung Galaxy Tab A, my PC is on Ubuntu.
Update: After some more tests, I determined that if when I plug the tablet to the PC by USB, the tablet screen is turned on, it works fine. However if I plug the tablet with the screen off, the issue described above occurs.
This is a workaround more than a fix, but it works for me on another Samsung device.
Install Samsung SideSync app from the Google play store on your device, then install Samsung SideSync app on your PC (http://www.samsung.com/sidesync).
After one more "allow access" popup, it won't ask again as the SideSync app will keep the allow access permission open.