On Thu, Dec 28, 2017 at 11:08:27AM +0100, Christoph Biedl wrote:

Just a heads-up to avoid more people lose hours in debugging:

After upgrading from 4.9 to 4.14 I noticed USB support was broken on my Allwinner A20 boards like Cubietruck and first generation BananaPi. There is simply no output of the lsusb command, and subsequently no connected USB devices are detected.

Bisecting led to

commit 6254a6a94489c4be717f757bec7d3a372cba1b6e Author: Arnd Bergmann arnd@arndb.de Date: Thu Apr 27 21:11:48 2017 +0200

power: supply: axp20x_usb_power: add IIO dependency

which already happened in the 4.12 development. Turns out after that commit "make oldconfig" will silently drop CONFIG_AXP20X_POWER unless CONFIG_IIO is set - but CONFIG_AXP20X_POWER is needed for USB on these boards.

Solution: Enable CONFIG_IIO, but no particular driver is required. I'm not aware whether it's possible to provide a smoother upgrade path in Kconfig, "selects" instead of "depends" might have been an option.

Try letting the authors of that patch know about this please.

thanks,

greg k-h