> Il giorno 25 mar 2017, alle ore 08:21, Lars Melin <lars...@gmail.com> ha > scritto: > >> >> The usb device has been disconnected, why it still cares about VBUS >> power? > > Morphing devices (3G dongles, wifi dongles, some printers) boots up in > install mode, usually only as a virtual cd-rom containing Windows drivers and > software. > [...] > why a host only configured port should cut the VBUS supply, it could be > always on right? >
Yes, that’s exactly the problem I tried to solve with this patch. I have to add that the problem was not there with kernels up to 4.8.17, I started to see it with 4.9 and up. By git-bisecting kernel sources, it appears this behaviour has been introduced by this commit: 2f3fd2c5bde1f94513c3dc311ae64494085ec371 I also agree that, in my opinion, a host only port should never remove the VBUS supply, as it happens on all the PCs (linux+windows+mac) that I tested until now. I saw this problem on a beaglebone black. Of course I’m available to do all the tests that you might suggest me to help you better understand the issue. Moreno Bartalucci
