I was testing a number of cameras with gphoto2 on Ubuntu Desktop 18.04LTS and Ubuntu Server 19.04 (updated to current for 5-13-2019).
A Nikon D7200, a Sony A6300 and a Canon M50 all APS-C 24Mpx.
I tested a Nikon D7200 and it worked fine, in M mode using a compatible USB cable.
I tested a rented Sony A6300 mirrorless (version 2.01 firmware) with a microUSB cable in Mass Storage, MTP and PC-remote mode using the exact same Ubuntu installs in Oracle VirtualBox 6, on Windows 10 (fully up to date as of 5-12-2019) and with the Oracle VirtualBox Extensions to support USB2 installed (please note I did test in USB1.1 as well).
I've attached to this bug report a tar.gz with a couple of debug files and a dump of the 'gphoto -v' from the Ubuntu 19.04 install. It's seemingly the latest build of Gphoto2 available.
With the current build of gphoto2 installed by default using apt-get on Ubuntu Server (or Desktop) 19.04, I get nothing but PTP timeout errors in PC-remote USB mode except for --auto-detect.
The older build from 18.04LTS would cause the Sony A6300 to shutdown after each command and it still didn't work correctly in the PC-remote mode.
Using the Ubuntu Desktop OS I was careful to do a 'pkill -f gphoto2' before each command.
I didn't have this need in the Ubuntu Server OS.
In short I can't use gphoto2 with a Sony A6300, and the current builds, to control any of the features listed on the compatibility matrix for gphoto2 as available in PC-remote USB mode as they all produce PTP timeouts.
I rented this camera, because I noted there are other Sony cameras reporting vaguely similar issues that are open right now. I wanted to know for a personal project if I would be forced to use the Sony API on their private WiFi from the camera (that API is JSON based, discontinued in newer models after the A6500 and worked just fine). As I rented the camera in question I won't be able to provide additional information after 11 AM EST tomorrow 5-14-2019 when I return it to BorrowLenses.
Please also note I tested this rented Sony A6300 camera with the Sony Imaging Edge software over USB to the Windows 10 on that system and it worked perfectly. So there shouldn't be anything wrong with the camera or the multiple PC USB ports I tested the camera with. The version of Imaging Edge tested was downloaded 5/13/2019. I also tested Imaging Edge for Mobile (Android) to the WiFi API in addition to my tests of that API with curl/Python 2.7 from Windows 10 and the Ubuntu OS VMs.
Last edit: Brian Binovsky 2019-05-13
Additionally I tested starting the camera in Sony Imaging Edge in Windows 10. Let it transition to connected in PC-remote mode. Then connecting it to the Ubuntu OS VMs (Desktop & Server) and it still got PTP timeouts. Even though it was partly initialized. I also tried different microUSB cables.
Hence I fully expect this is a bug in gphoto2.
i own sony A6000, A6300, RX0; all have the exact problem, can not access files, can not download files. attaching "gphoto2 --list-files --debug" with SONY RX0 camera here.
in pc remote control mode you can only capture, but not access the files on the sd card.
you need to switch to PTP/MTP mode or Storage mode to retrieve files from the camera