From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: [BACKPORT 4.14.y 04/18] usb: dwc3: Allow disabling of metastability workaround Date: Mon, 11 Nov 2019 10:16:24 +0100 Message-ID: <20191111091624.GA4139389@kroah.com> References: <20190905161759.28036-1-mathieu.poirier@linaro.org> <20190905161759.28036-5-mathieu.poirier@linaro.org> <20190910143601.GD3362@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Mathieu Poirier Cc: "# 4 . 7" , linux-usb@vger.kernel.org, Linux Kernel Mailing List , linux-pm@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-omap@vger.kernel.org, linux-i2c@vger.kernel.org, linux-pci@vger.kernel.org, linux-mtd@lists.infradead.org List-Id: linux-i2c@vger.kernel.org On Wed, Sep 11, 2019 at 08:01:40AM -0600, Mathieu Poirier wrote: > On Tue, 10 Sep 2019 at 08:36, Greg KH wrote: > > > > On Thu, Sep 05, 2019 at 10:17:45AM -0600, Mathieu Poirier wrote: > > > From: Roger Quadros > > > > > > commit 42bf02ec6e420e541af9a47437d0bdf961ca2972 upstream > > > > > > Some platforms (e.g. TI's DRA7 USB2 instance) have more trouble > > > with the metastability workaround as it supports only > > > a High-Speed PHY and the PHY can enter into an Erratic state [1] > > > when the controller is set in SuperSpeed mode as part of > > > the metastability workaround. > > > > > > This causes upto 2 seconds delay in enumeration on DRA7's USB2 > > > instance in gadget mode. > > > > > > If these platforms can be better off without the workaround, > > > provide a device tree property to suggest that so the workaround > > > is avoided. > > > > > > [1] Device mode enumeration trace showing PHY Erratic Error. > > > irq/90-dwc3-969 [000] d... 52.323145: dwc3_event: event (00000901): Erratic Error [U0] > > > irq/90-dwc3-969 [000] d... 52.560646: dwc3_event: event (00000901): Erratic Error [U0] > > > irq/90-dwc3-969 [000] d... 52.798144: dwc3_event: event (00000901): Erratic Error [U0] > > > > Does the DT also need to get updated with this new id for this? Is that > > a separate patch somewhere? > > The upstream commit is: > > b8c9c6fa2002 ARM: dts: dra7: Disable USB metastability workaround for USB2 > > Should I just send the latter or you prefer a resend with both patches? I've queued this up now, along with the rest of this series, thanks. greg k-h