From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758051AbdJKUr2 (ORCPT ); Wed, 11 Oct 2017 16:47:28 -0400 Received: from mail-qt0-f172.google.com ([209.85.216.172]:48544 "EHLO mail-qt0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752614AbdJKUrX (ORCPT ); Wed, 11 Oct 2017 16:47:23 -0400 X-Google-Smtp-Source: AOwi7QDJxAMp9swebpLRDLwW/thwXgGoFpBZzMyBULhgg9vLJmyV7OV7Hg60C4iaaUnWkhha3aufTg== Message-ID: <1507754838.19342.11.camel@ndufresne.ca> Subject: Re: [PATCH v3 1/2] staging: Introduce NVIDIA Tegra20 video decoder driver From: Nicolas Dufresne To: Dmitry Osipenko , Thierry Reding , Jonathan Hunter , Greg Kroah-Hartman , Rob Herring , Mauro Carvalho Chehab , Stephen Warren Cc: Dan Carpenter , linux-media@vger.kernel.org, linux-tegra@vger.kernel.org, devel@driverdev.osuosl.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 11 Oct 2017 16:47:18 -0400 In-Reply-To: <3d432aa2617977a2b0a8621a1fc2f36f751133e1.1507752381.git.digetx@gmail.com> References: <3d432aa2617977a2b0a8621a1fc2f36f751133e1.1507752381.git.digetx@gmail.com> Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-hQ+YrLKtwEhINVxeVYTt" X-Mailer: Evolution 3.24.6 (3.24.6-1.fc26) Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-hQ+YrLKtwEhINVxeVYTt Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Le mercredi 11 octobre 2017 =C3=A0 23:08 +0300, Dmitry Osipenko a =C3=A9cri= t : > diff --git a/drivers/staging/tegra-vde/TODO b/drivers/staging/tegra- > vde/TODO > new file mode 100644 > index 000000000000..e98bbc7b3c19 > --- /dev/null > +++ b/drivers/staging/tegra-vde/TODO > @@ -0,0 +1,5 @@ > +TODO: > + - Figure out how generic V4L2 API could be utilized by this > driver, > + implement it. > + That is a very interesting effort, I think it's the first time someone is proposing an upstream driver for a Tegra platform. When I look tegra_vde_h264_decoder_ctx, it looks like the only thing that the HW is not parsing is the media header (pps/sps). Is that correct ? I wonder how acceptable it would be to parse this inside the driver. It is no more complex then parsing an EDID. If that was possible, wrapping this driver as a v4l2 mem2mem should be rather simple. As a side effect, you'll automatically get some userspace working, notably GStreamer and FFmpeg. For the case even parsing the headers is too much from a kernel point of view, then I think you should have a look at the following effort. It's a proposal base on yet to be merged Request API. Hugues is also propose a libv4l2 adapter that makes the driver looks like a normal v4l2 m2m, hiding all the userspace parsing and table filling. This though, is long term plan to integrate state-less or parser-less encoders into linux-media. It seems rather overkill for state-full driver that requires parsed headers like PPS/SPS. https://lwn.net/Articles/720797/ regards, Nicolas --=-hQ+YrLKtwEhINVxeVYTt Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iF0EABECAB0WIQSScpfJiL+hb5vvd45xUwItrAaoHAUCWd6DVwAKCRBxUwItrAao HDQrAKDVFLfZTOGk1lK0E7rdaFkXPVUI1QCfasRs+MAVBvxhbQl6+N2IwHr2EkU= =I5vO -----END PGP SIGNATURE----- --=-hQ+YrLKtwEhINVxeVYTt--