Den 26.01.2016 17:55, skrev Alan Stern:
On Mon, 25 Jan 2016, Doug Anderson wrote:
...another interesting idea would be to try to see if you could just
change the configuration of the Raspberry Pi kernel to switch which
dwc2 driver it used. Presumably their driver was an addition on top
of the driver in "drivers/usb/dwc2". In fact, doing a 'git log' on
drivers/usb/dwc2 in the "rpi-4.4.y" kernel on github it looks pure
(and Stefan is even the last commit author!)
I'll try it. In case it works: There have been lots of patches from
you and John posted to linux-usb in the last couple of months; which
ones should I apply for testing on top of d51c7d840b002? (That was the
top commit on the master branch at the time I shallow-cloned the
Raspberry Pi kernel from github -- looks like it's based on 4.1.15.)
It's possible it makes more sense to switch to the 4.4 RPI kernel
first to make thing simpler? Presumably that would have fewer patches
to try applying atop.
I installed the rpi-4.4.y branch from the
https://github.com/raspberrypi/linux repository. As is, it generated a
working kernel. Then I tried editing the config; I removed
CONFIG_USB_DWCOTG and added CONFIG_USB_DWC2 and CONFIG_USB_DWC2_HOST.
However, when I booted the resulting kernel it didn't seem to detect
the host controller at all. No USB devices were probed, which meant no
working ethernet or keyboard.
Then I tried enabling both drivers in the config. That worked, but the
controller was bound to dwc_otg, not to dwc2.
I get the feeling that some magic DT incantation is missing, although I
have no idea what. The base bcm2709-rpi-2-b.dtb wasn't affected by the
config change, nor was the overlays/dwc2-overlay.dtb file.
Any suggestions?
Have you enabled the dwc2 overlay?
Add to /boot/config.txt:
dtoverlay=dwc2
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