Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753842AbcCSKK2 (ORCPT ); Sat, 19 Mar 2016 06:10:28 -0400 Received: from 212-186-180-163.dynamic.surfer.at ([212.186.180.163]:47996 "EHLO cgate.sperl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752335AbcCSKKU convert rfc822-to-8bit (ORCPT ); Sat, 19 Mar 2016 06:10:20 -0400 Subject: Re: [RFT PATCH 2/2] Revert "usb: dwc2: Fix probe problem on bcm2835" Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2104\)) Content-Type: text/plain; charset=utf-8 From: Martin Sperl X-Priority: 3 In-Reply-To: <376411469.89406.35996342-72cd-48a5-8893-944da9f8a599.open-xchange@email.1und1.de> Date: Sat, 19 Mar 2016 11:10:16 +0100 Cc: Eric Anholt , Michael Niewoehner , Tao Huang , John Youn , Julius Werner , Greg Kroah-Hartman , "linux-kernel@vger.kernel.org" , "linux-usb@vger.kernel.org" , Caesar Wang , Doug Anderson , Heiko Stuebner , Felipe Balbi , Remi Pommarel Content-Transfer-Encoding: 8BIT Message-Id: <0AE41019-8E21-4C39-B21F-51CD08C1A3DF@martin.sperl.org> References: <1457115786-11370-1-git-send-email-dianders@chromium.org> <1457115786-11370-2-git-send-email-dianders@chromium.org> <1400647253.149212.b3bb45b6-c852-4cf1-9d3e-9fb299176369.open-xchange@email.1und1.de> <941828343.8833.cdbd40c7-e6f4-4b3e-9665-30fc6680f6e0.open-xchange@email.1und1.de> <56E1C79D.3090104@synopsys.com> <56E9A5E8.7090102@synopsys.com> <1440674775.86542.7bdab192-0ed1-49f2-8559-819af7131cbd.open-xchange@email.1und1.de> <87fuvn1a9p.fsf@eliezer.anholt.net> <8E14A795-8C35-4C4D-8D3A-09F29EE42A5F@martin.sperl.org> <376411469.89406.35996342-72cd-48a5-8893-944da9f8a599.open-xchange@email.1und1.de> To: Stefan Wahren X-Mailer: Apple Mail (2.2104) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1947 Lines: 56 > On 19.03.2016, at 10:52, Stefan Wahren wrote: > > Hi, > >> Martin Sperl hat am 19. März 2016 um 08:44 >> geschrieben: >> >> >> >>> On 19.03.2016, at 03:17, Eric Anholt wrote: >>> >>> Stefan Wahren writes: >>> >>>> Hi Eric, >>>> hi Martin, >>>> >>>>> John Youn 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? I did not have any problems with USB recently (using 4.5), so I would not have any idea how to reproduce it. Note that I am using it with an AXIS USB-ethernet dongle plus USB-stick all the time on my Compute Module connected via a tiny hub, so I wonder if that qualifies as being able to trigger the issue... Martin