Re: [RFT PATCH 2/2] Revert "usb: dwc2: Fix probe problem on bcm2835"

[Doug Anderson]

Stefan,

On Mon, Mar 7, 2016 at 10:40 AM, Stefan Wahren <stefan.wahren@xxxxxxxx> wrote:
> Hi Doug,
>
>> Douglas Anderson <dianders@xxxxxxxxxxxx> hat am 4. MÃrz 2016 um 19:23
>> geschrieben:
>>
>>
>> This reverts commit 192cb07f7928 ("usb: dwc2: Fix probe problem on
>> bcm2835") now that we've found the root cause. See the change
>> titled ("usb: dwc2: Add a 10 ms delay to dwc2_core_reset()").
>
> adding a delay of 10 ms after a core reset might be a idea, but applying both
> patches breaks USB support on RPi :-(
>
> I'm getting the wrong register values ...

Ugh.  :(

Just out of curiosity, if you loop and time long it takes for the
registers to get to the right state after reset, what do you get?
AKA, pick:

https://chromium-review.googlesource.com/331260

...and let me know what it prints out.  On my system I see:

[    1.990743] dwc2 ff540000.usb: Waited 300001 us, 0x04000400 =>
0x04000400, 0x02000800 => 0x02000800
[    2.119677] dwc2 ff580000.usb: Waited 9997 us, 0x00100400 =>
0x04000400, 0x00000000 => 0x02000800

I believe the difference in behavior is because of the two different
types of USB controllers (one is OTG and the other is host only).


-Doug