From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sowjanya Komatineni Subject: Re: [RFC PATCH v6 6/9] media: tegra: Add Tegra210 Video input driver Date: Mon, 6 Apr 2020 13:30:54 -0700 Message-ID: <0227d65f-283a-1488-a48c-7bab600eae35@nvidia.com> References: <1585963507-12610-1-git-send-email-skomatineni@nvidia.com> <1585963507-12610-7-git-send-email-skomatineni@nvidia.com> <38d921a7-5cdf-8d0a-2772-4399dd1a96a0@gmail.com> <9b8cf37b-d2ad-9df2-aad8-216c2c954e69@nvidia.com> <1a12974a-7cc7-2c3a-3995-076b9956714d@gmail.com> <66cc8646-43d3-3fc8-c31d-d0d2efac505f@nvidia.com> <9038ce90-ac53-93e7-ce65-57f6ff1e9b30@nvidia.com> <36b5627a-8639-6244-8620-4f23828e0638@nvidia.com> <1c2c921e-daef-ba0f-5d1a-b58aa0b940fb@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <1c2c921e-daef-ba0f-5d1a-b58aa0b940fb@gmail.com> Content-Language: en-US Sender: linux-clk-owner@vger.kernel.org To: Dmitry Osipenko , thierry.reding@gmail.com, jonathanh@nvidia.com, frankc@nvidia.com, hverkuil@xs4all.nl, sakari.ailus@iki.fi, helen.koike@collabora.com Cc: sboyd@kernel.org, linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-clk@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-tegra@vger.kernel.org On 4/6/20 1:28 PM, Dmitry Osipenko wrote: > External email: Use caution opening links or attachments > > > 06.04.2020 23:05, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > .. >>>> Wait time for HW syncpt to reach threshold is tuned to work for all >>>> frame rates. So if increment doesn't happen by then, its definitely >>>> missed event. >>> This is questionable. Technically, speculating about whether the tuned >>> value is good for all possible cases is incorrect thing to do. >>> >>> Although, I guess in practice it should be good enough for the starter >>> and could be improved later on, once the host1x driver will be improved= . >> By tuned value I meant about 200ms wait timeout for frame event to >> happen is what we have been using in downstream and with BSP release >> images which works good for all sensors and bridges we supported so far. > I don't know anything about the state of today's downstream, but > downstream of older Tegra SoCs was pretty awful in regards to the host1x > syncing, unfortunately it was borrowed into the upstream host1x years > ago and nothing was done about it so far. I'd suggest to be careful > about it. 200ms timeout we wait for event to happen is the case even with=20 T186/T194 as well and internally it was tuned from lots of testing with=20 various sensors and frame rate computations which is known to work good.