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

[Martin Sperl]

> On 19.03.2016, at 03:17, Eric Anholt <eric@xxxxxxxxxx> wrote:
> 
> Stefan Wahren <stefan.wahren@xxxxxxxx> writes:
> 
>> Hi Eric,
>> hi Martin,
>> 
>>> John Youn <John.Youn@xxxxxxxxxxxx> hat am 16. MÃrz 2016 um 19:28 geschrieben:
>>> 
>>> 
>>> On 3/10/2016 11:14 AM, John Youn wrote:
>>>> On 3/9/2016 11:06 AM, Doug Anderson wrote:
>>>>> 
>>>>> John: it's pretty clear that there's something taking almost exactly
>>>>> 10ms on my system and almost exactly 50ms on Stefan's system. Is
>>>>> there some register we could poll to see when this process is done?
>>>>> ...or can we look at the dwc2 revision number / feature register and
>>>>> detect how long to delay?
>>>>> 

Maybe this difference is related to overclocking settings in the firmware?

>>> 
>>> 1. What is the AHB Clock frequency? Is the AHB Clock gated during
>>> Reset?
> 
> Low confidence here as I'm tracing lines across a ton of modules, but it
> looks like it comes from the USB AXI clock in peri_image, which is a
> gate on the normal 250Mhz APB clock, but nothing should be touching that
> gate register as part of USB reset as far as I know.
> 
Isnât it possible that this clock (probably BCM2835_CLOCK_VPU) is 
changed by the firmware due to overclocking settings in /boot/config.txt?

Martin