From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 09CCBC5478C for ; Wed, 28 Feb 2024 16:14:09 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4119C10E713; Wed, 28 Feb 2024 16:14:08 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="IF29Uk+V"; dkim-atps=neutral Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9DA3F10E713 for ; Wed, 28 Feb 2024 16:14:06 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id C954BCE12A1; Wed, 28 Feb 2024 16:14:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8BCCC433C7; Wed, 28 Feb 2024 16:14:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1709136844; bh=+5C3vqa46Z5TueGROchrOvaCvAo76c8wgPV51Z2KIGk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=IF29Uk+Vy1iQLc3TQ+atArn7bdmZj6yahnQjdhYGcsd0/SSi/iawTZauHyg6Ymw8V 2iDS/Kg9dGoibjE5vPPc65LJII0QWE2Fd9pIoS/HWtArrJxD7gu/XG8WLvnxPCrAcA nBObrXI8i8+NDt2hEBJv0tZaJ2wiasPBy2jkxyc3O0+ZoXtkwyPpWNchqybJSelxeI nESehopb5bztSkIksYrz/utYZJvRw1Pa2NZVtj06cKrkCczfMb9MLjLQszvkzlH8BP E4GCuiTy52eeU+qL83deT9FS/ylbZdJSPKoH/yPMXQhBaQdXQMV8glTNH38qGOj2Fk jv4Ib5rF/GwwQ== Date: Wed, 28 Feb 2024 17:14:01 +0100 From: Maxime Ripard To: Simon Ser Cc: Dave Stevenson , Pekka Paalanen , dri-devel@lists.freedesktop.org, Maarten Lankhorst , Thomas Zimmermann , Nick Hollinghurst Subject: Re: UAPI Re: [PATCH 1/3] drm: Add DRM_MODE_TV_MODE_MONOCHROME Message-ID: <20240228-nice-flat-cormorant-badff7@houat> References: <20240216184857.245372-1-dave.stevenson@raspberrypi.com> <20240216184857.245372-2-dave.stevenson@raspberrypi.com> <20240221110751.48da8190@eldfell> <20240226171143.27e60c30@eldfell> <5us3AK9XJ5zu1AOKQeZxKWsK0f6Xtm7vHWttRTFPRo57Ph5WO62deVIK8TrkQIFmjFMrn-a2qusgP3W74dV6SKTA5OdTt4zncR7J2qQ_Qck=@emersion.fr> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="iwivmlctecqyfcwu" Content-Disposition: inline In-Reply-To: <5us3AK9XJ5zu1AOKQeZxKWsK0f6Xtm7vHWttRTFPRo57Ph5WO62deVIK8TrkQIFmjFMrn-a2qusgP3W74dV6SKTA5OdTt4zncR7J2qQ_Qck=@emersion.fr> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" --iwivmlctecqyfcwu Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, On Tue, Feb 27, 2024 at 09:51:06AM +0000, Simon Ser wrote: > On Monday, February 26th, 2024 at 18:23, Dave Stevenson wrote: > > > and I've also completely missed any kernel command line > > > arguments manipulating KMS properties. > >=20 > > "tv_mode" on the command line is handled in > > drm_mode_parse_cmdline_options() [3], as are rotate, reflect_x, > > reflect_y, margin_[left|right|top|bottom], and panel_orientation all > > to set the relevant KMS properties. > >=20 > > Having "video=3DComposite-1:PAL,tv_mode=3DMono" on the kernel command l= ine > > will set up connector Composite-1 with the standard 720x576 50Hz > > interlaced timings, and DRM_MODE_TV_MODE_MONOCHROME selected on the > > tv_mode property. Swap in different tv_mode descriptions as required > > (eg PAL,tv_mode=3DSECAM), although some make little sense. > >=20 > > That's the main route I'm looking at for configuring this property, > > for situations such as having a black and white TV connected. You > > don't get the opportunity to interrogate a composite display over what > > it supports, so it has to be configured manually somewhere in the > > system. If your monitor doesn't support the system default, then you > > can't see a GUI in order to change the option, and there is no > > guaranteed supported configuration so the command line is about the > > only option. > >=20 > > The use cases for runtime switching of the "tv_mode" are exceedingly > > rare, so IMHO the property doesn't need exposing through the UAPI. > > However it was added to the UAPI about 8 years ago for vc4 and sunxi, > > and is also now used by other drivers, so can't be reverted. Does that > > mean it can now never be changed without jumping through the hoop of > > creating some userspace user? >=20 > I don't know what the rules were 8 years ago, but the current uAPI rules > are what they are, and a new enum entry is new uAPI. TBF, and even if the wayland compositors support is missing, this property is perfectly usable as it is with upstream, open-source code, through either the command-line or X.org, and it's documented. So it's fine by me from a UAPI requirement side. Maxime --iwivmlctecqyfcwu Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCZd9byAAKCRDj7w1vZxhR xS+rAQC3pv4X/pZYkwS3813abI/HCnD/jUXKh/M9hptl1+NUAwEAwICyoyWFuXRC HnfJKHzq7c2riNgK9SixO6u+sFrC1wI= =EIhy -----END PGP SIGNATURE----- --iwivmlctecqyfcwu--