Bug in split transactions on Raspberry Pi

[Noralf Trønnes]

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