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

From	Stefan Wahren <stefan.wahren@i2se.com>
Newsgroups	linux.kernel
Subject	Re: [RFT PATCH 2/2] Revert "usb: dwc2: Fix probe problem on bcm2835"
Date	2016-03-19 11:00 +0100
Message-ID	<relPQ-6uw-9@gated-at.bofh.it> (permalink)
References	(6 earlier) <rbehQ-2Wa-21@gated-at.bofh.it> <rdomK-4bz-21@gated-at.bofh.it> <rebQt-3io-13@gated-at.bofh.it> <reeEF-7K5-7@gated-at.bofh.it> <rejO2-571-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Hi,

> Martin Sperl <kernel@martin.sperl.org> hat am 19. März 2016 um 08:44
> geschrieben:
>
>
>
> > On 19.03.2016, at 03:17, Eric Anholt <eric@anholt.net> wrote:
> >
> > Stefan Wahren <stefan.wahren@i2se.com> writes:
> >
> >> Hi Eric,
> >> hi Martin,
> >>
> >>> John Youn <John.Youn@synopsys.com> hat am 16. März 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.
> >
> Isn’t it possible that this clock (probably BCM2835_CLOCK_VPU) is
> changed by the firmware due to overclocking settings in /boot/config.txt?

i don't use any overclocking settings. 

Are you able to reproduce the behavior on your Pi?

Stefan

>
> Martin
>
>

Thread

Re: [RFT PATCH 2/2] Revert "usb: dwc2: Fix probe problem on  bcm2835" Stefan Wahren <stefan.wahren@i2se.com> - 2016-03-19 00:20 +0100
  Re: [RFT PATCH 2/2] Revert "usb: dwc2: Fix probe problem on bcm2835" Eric Anholt <eric@anholt.net> - 2016-03-19 03:20 +0100
    Re: [RFT PATCH 2/2] Revert "usb: dwc2: Fix probe problem on bcm2835" Martin Sperl <kernel@martin.sperl.org> - 2016-03-19 08:50 +0100
      Re: [RFT PATCH 2/2] Revert "usb: dwc2: Fix probe problem on  bcm2835" Stefan Wahren <stefan.wahren@i2se.com> - 2016-03-19 11:00 +0100
        Re: [RFT PATCH 2/2] Revert "usb: dwc2: Fix probe problem on bcm2835" Martin Sperl <kernel@martin.sperl.org> - 2016-03-19 11:20 +0100
          Re: [RFT PATCH 2/2] Revert "usb: dwc2: Fix probe problem on  bcm2835" Stefan Wahren <stefan.wahren@i2se.com> - 2016-03-19 13:20 +0100
    Re: [RFT PATCH 2/2] Revert "usb: dwc2: Fix probe problem on  bcm2835" Stefan Wahren <stefan.wahren@i2se.com> - 2016-03-19 10:50 +0100

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