From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nagarjuna Kristam Subject: Re: [PATCH V1 4/4] usb: gadget: tegra-xudc: add port_speed_quirk Date: Mon, 4 May 2020 09:33:37 +0530 Message-ID: <691d5a8e-0ca8-e763-9b85-54625db84076@nvidia.com> References: <1587022460-31988-1-git-send-email-nkristam@nvidia.com> <1587022460-31988-5-git-send-email-nkristam@nvidia.com> <20200428122512.GN3592148@ulmo> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20200428122512.GN3592148@ulmo> Content-Language: en-US Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Thierry Reding Cc: balbi-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@vger.kernel.org On 28-04-2020 17:55, Thierry Reding wrote: > > On Thu, Apr 16, 2020 at 01:04:20PM +0530, Nagarjuna Kristam wrote: >> Add port_speed_quirk that modify below registers to limit/restore OTG >> port speed to GEN1/GEN2. >> SSPX_CORE_CNT56 >> SSPX_CORE_CNT57 >> SSPX_CORE_CNT65 >> SSPX_CORE_CNT66 >> SSPX_CORE_CNT67 >> SSPX_CORE_CNT72 >> >> The basic idea is to make SCD intentionally fail, reduce SCD timeout and >> force device transit to TSEQ. Enable this flag to only Tegra194. >> >> Based on work by WayneChang >> >> Signed-off-by: Nagarjuna Kristam >> --- >> drivers/usb/gadget/udc/tegra-xudc.c | 106 ++++++++++++++++++++++++++++++++++++ >> 1 file changed, 106 insertions(+) > You're telling readers what you're doing, but after reading the commit > message, I have no idea why this is being done. Can you provide more > information on why exactly is this needed? Why do we have to limit the > OTG port speed? > > Thierry Will re-word the commit message to explain on why this is needed. Thanks, Nagarjuna