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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D49EC2BA19 for ; Wed, 15 Apr 2020 07:33:35 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id CEA2D20775 for ; Wed, 15 Apr 2020 07:33:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CEA2D20775 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0BC526E864; Wed, 15 Apr 2020 07:33:34 +0000 (UTC) Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2DD126E864 for ; Wed, 15 Apr 2020 07:33:32 +0000 (UTC) IronPort-SDR: y7oXLXC+Ye7daj79mykWzhLSUuKJIZtk2qaU7516xty2RxJN81oB9oek6yr+vXIeR9jP/FBNJF sxjHTPBgb/aA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Apr 2020 00:33:32 -0700 IronPort-SDR: 9LZ/+cGlJal2nOD6KrYU8t20P/pQz48b1fG4ws+BB68kWPKKEZGu8jsE4yebXpEkxDTLpQ0Kon FTvkvZc4Ea4A== X-IronPort-AV: E=Sophos;i="5.72,386,1580803200"; d="scan'208";a="427347028" Received: from ssolodk-mobl1.ccr.corp.intel.com (HELO localhost) ([10.252.48.37]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Apr 2020 00:33:28 -0700 From: Jani Nikula To: Yussuf Khalil , Daniel Vetter Subject: Re: [PATCH 5/5] drm/i915: Replace "Broadcast RGB" with "RGB quantization range" property In-Reply-To: <2cfe44c96818515939050ad19e9c248e50519be2.camel@pp3345.net> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20200413214024.46500-1-dev@pp3345.net> <20200413214024.46500-6-dev@pp3345.net> <87ftd6mi3e.fsf@intel.com> <87d08amhy5.fsf@intel.com> <20200414123404.GT3456981@phenom.ffwll.local> <2cfe44c96818515939050ad19e9c248e50519be2.camel@pp3345.net> Date: Wed, 15 Apr 2020 10:33:25 +0300 Message-ID: <87r1wp5hkq.fsf@intel.com> MIME-Version: 1.0 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: , Cc: David Airlie , "linux-kernel@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , Thomas Zimmermann Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Tue, 14 Apr 2020, Yussuf Khalil wrote: > On Tue, 2020-04-14 at 14:34 +0200, Daniel Vetter wrote: >> On Tue, Apr 14, 2020 at 02:21:06PM +0300, Jani Nikula wrote: >> > On Tue, 14 Apr 2020, Jani Nikula >> > wrote: >> > > On Mon, 13 Apr 2020, Simon Ser wrote: >> > > > On Monday, April 13, 2020 11:40 PM, Yussuf Khalil < >> > > > dev@pp3345.net> wrote: >> > > > >> > > > > DRM now has a globally available "RGB quantization range" >> > > > > connector >> > > > > property. i915's "Broadcast RGB" that fulfils the same >> > > > > purpose is now >> > > > > considered deprecated, so drop it in favor of the DRM >> > > > > property. >> > > > >> > > > For a UAPI point-of-view, I'm not sure this is fine. Some user- >> > > > space >> > > > might depend on this property, dropping it would break such >> > > > user-space. >> > > >> > > Agreed. >> > > >> > > > Can we make this property deprecated but still keep it for >> > > > backwards >> > > > compatibility? >> > > >> > > Would be nice to make the i915 specific property an "alias" for >> > > the new >> > > property, however I'm not sure how you'd make that happen. >> > > Otherwise >> > > juggling between the two properties is going to be a nightmare. >> > >> > Ah, the obvious easy choice is to use the property and enum names >> > already being used by i915 and gma500, and you have no problem. >> > Perhaps >> > they're not the names you'd like, but then looking at the total >> > lack of >> > consistency across property naming makes them fit right in. ;) >> >> Yeah if we don't have contradictory usage across drivers when >> modernizing >> these properties, then let's just stick with the names already there. >> It's >> not pretty, but works better since more userspace/internet howtos >> know how >> to use this stuff. >> -Daniel > > Note that i915's "Broadcast RGB" isn't the same as gma500's: i915 has an > "Automatic" option, whereas gma500 does not. Adding "Automatic" option that just defaults to "Full" in gma500 does not break existing userspace, but allows for extending it to do more clever things later. > Also, radeon has a property called > "output_csc" that fulfills a similar purpose. Looking at the code, though, it > seems that radeon does not adhere to the standard correctly (or I am missing > something). > > An alternative would be to leave the existing driver-specific properties and > change them to be pseudo-aliases for the "RGB quantization range" property. > This can be done by letting the drivers read from and write to the new property > when user-space tries to read or modify the driver's property. This way we could > retain full backwards compatibility for all drivers equally. > > What do you think? I'm obviously biased and predisposed to avoid adding extra complexity to i915 when it's not necessary. We'd have *two* connector properties for the same thing until the end of time, even if one is an alias for the other. BR, Jani. -- Jani Nikula, Intel Open Source Graphics Center _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel