Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758136AbeAINxa (ORCPT + 1 other); Tue, 9 Jan 2018 08:53:30 -0500 Received: from mail.free-electrons.com ([62.4.15.54]:57355 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758079AbeAINxY (ORCPT ); Tue, 9 Jan 2018 08:53:24 -0500 Date: Tue, 9 Jan 2018 14:53:22 +0100 From: Maxime Ripard To: Chen-Yu Tsai , Daniel Vetter , Jani Nikula , Sean Paul , Thomas Petazzoni , Boris Brezillon , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Laurent Pinchart , linux-arm-kernel@lists.infradead.org, thomas@vitsch.nl Subject: Re: [PATCH 06/19] drm/blend: Add a generic alpha property Message-ID: <20180109135322.7lb3snbxfcezobhz@flea> References: <5c765fc730d75cb362dc37bcdb3b3aeacc7bdb30.1515494838.git-series.maxime.ripard@free-electrons.com> <20180109123241.GU26573@phenom.ffwll.local> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="mil4k24fivakc7vh" Content-Disposition: inline In-Reply-To: <20180109123241.GU26573@phenom.ffwll.local> User-Agent: NeoMutt/20171215 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: --mil4k24fivakc7vh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jan 09, 2018 at 01:32:41PM +0100, Daniel Vetter wrote: > On Tue, Jan 09, 2018 at 11:56:25AM +0100, Maxime Ripard wrote: > > Some drivers duplicate the logic to create a property to store a per-pl= ane > > alpha. > >=20 > > Let's create a helper in order to move that to the core. > >=20 > > Cc: Boris Brezillon > > Cc: Laurent Pinchart > > Signed-off-by: Maxime Ripard >=20 > Do we have userspace for this? Wayland seems to be on its way to implement this, with ChromeOS using it: https://lists.freedesktop.org/archives/wayland-devel/2017-August/034741.html and more specifically: https://chromium.googlesource.com/chromium/src/+/master/third_party/wayland= -protocols/unstable/alpha-compositing/alpha-compositing-unstable-v1.xml#118 > Is encoding a fixed 0-255 range really the best idea? I don't really know, is there hardware or formats where there is more than 255? Or did you mean less than that? > I know other drivers have skimped on the rules here a bit ... But at least > internally (i.e. within the drm_plane_state) we probably should restrict > ourselves to u8. And this needs real docs (i.e. the full blend equation > drivers are supposed to implement). You mean straight vs premultiplied? Maybe we should implement this as an additional property in read only depending on how the hardware behaves? Thanks! Maxime --=20 Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com --mil4k24fivakc7vh Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEE0VqZU19dR2zEVaqr0rTAlCFNr3QFAlpUyVEACgkQ0rTAlCFN r3SkuA//TLEjxrhOd1oeo0mu5/HdtX97s/L+RJAM+DAtfvgLAitPHAl3fy46vSJz TI9/KZ74BDG7CZVsranPRPl/h1pIP7lRFT78AphaxRYvtj42dxBZqvzzz+fLpg43 kd6cj7JuMujNA9k0tMLLC77JpkvRhyyvyl8GQxJ/qCyFT/OfWmSfUJkE4AeHs7r8 dA1NEyZPnuA5S0zsZwk9JR7fQ5WYh5PMG9CUK7N60CnHbTx1C/H3bmiRD7pSAEY9 4+eGZ4iCy8ECVs+wW+2GDaN7PrBSAch6PnSZGqfnxBwewLhOx0bmP/N0/00TIi3E 6YAUeJr0arpITud8bL1SnVan5Irn1wMR25+Tg3ZxRbZFsWOiiFxTlzbscfOa3788 q0cGQ1aBC69L69Sx/mAn8eJuBtLsDWIM6fXOWzOxGEO4/XBnvE/YDWM16ZPmTeEi ls8kO1nVk2p1FZzcckaWzbFkZgwaXWAfNd1EXwSTs+Yz/HmfAsL54ibLnnh57Cd/ VDl1adzPs+GpVEyRn2jMSpD9KS6RBtSyfRfdf5VRSIcnswisJDT8RJ5V7lr7U05V YfvRiqKQ84a15d1LyDt1XJmpLLfX9KVUKpWsxZdrIXOwVaU1yYNsjf2ebiAOwsL5 FZM5LhQZwfgdo4uuYpLgZ4wv0dxpFXXAlX7g0bRVzyLwY1b7FUM= =abKz -----END PGP SIGNATURE----- --mil4k24fivakc7vh--