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 5ECF6CF9C6F for ; Tue, 24 Sep 2024 13:37:11 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0AB6D10E2B3; Tue, 24 Sep 2024 13:37:11 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="fkcCF5Wq"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.11]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8C20510E2B3; Tue, 24 Sep 2024 13:37:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1727185030; x=1758721030; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version:content-transfer-encoding; bh=7fV+iCqiE6ZBBD3NcPWw32VpBvl0FZm3N99aDbwvktk=; b=fkcCF5Wqw4A6TBGx7tLcnHK4ti90EfR/EMyweAZcLwn4MlnNHX5c8amH LVUhw1Zio6mzFaJoRa4UzsUb8SwPDAeU51YQSGdjkNIrK7GvlPPnE3pp7 7RIZ9rGfXqdfjR33f4gOLxTg0qAuC5op5JvTvGgPGkBHky5qqKkS3Q8md /9BvTYsHTVcYguPENJezo0M0YtupNgDk2eTs8ZUJJBJ/Ijl1ClOzcejBv +VuQXS8/fYvvxbtb9B4OdTsbkRD0miH3L67XFwfV55BXKwAjwAO/BOYJ4 zYHudNS9hAf+RAJOn15b6g0SPTnjPe175DjXaUkdvGGwMz0ooPrVfkZIU w==; X-CSE-ConnectionGUID: B69Dxz09Rz6MXj3jaBIqmA== X-CSE-MsgGUID: 232AyLJcQOSz0QBd2KKhDQ== X-IronPort-AV: E=McAfee;i="6700,10204,11205"; a="36765789" X-IronPort-AV: E=Sophos;i="6.10,254,1719903600"; d="scan'208";a="36765789" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Sep 2024 06:37:09 -0700 X-CSE-ConnectionGUID: AVu7XODATviWSXITDRV2fw== X-CSE-MsgGUID: evqxTUd/SYecNYpj7fqBiw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,254,1719903600"; d="scan'208";a="75812188" Received: from sschumil-mobl2.ger.corp.intel.com (HELO localhost) ([10.245.246.183]) by fmviesa005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Sep 2024 06:37:06 -0700 From: Jani Nikula To: Lucas De Marchi Cc: Ville =?utf-8?B?U3lyasOkbMOk?= , Rodrigo Vivi , intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org Subject: Re: [PATCH v2 0/9] drm/i915/display: platform identification with display->is. In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <87wmj14c0q.fsf@intel.com> Date: Tue, 24 Sep 2024 16:37:04 +0300 Message-ID: <87ldzh41hb.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On Tue, 24 Sep 2024, Lucas De Marchi wrote: > On Tue, Sep 24, 2024 at 12:49:25PM GMT, Jani Nikula wrote: >>On Thu, 29 Aug 2024, Ville Syrj=C3=A4l=C3=A4 wrote: >>> On Wed, Aug 28, 2024 at 04:41:24PM -0400, Rodrigo Vivi wrote: >>>> On Mon, Aug 19, 2024 at 09:44:27PM +0300, Jani Nikula wrote: >>>> > v2 of [1]. Please read the cover letter there. >>>> > >>>> > This addresses review comments and adds a few more commits on top, i= n particular >>>> > the last one showcasing the approach. >>>> > >>>> > The main question remains, is this what we want? >>>> >>>> I don't know why, but the 'is' thing is still strange. >>>> >>>> I know I know... I'm bad with naming myself. >>>> >>>> I think about 'platform' but that get too big >>>> >>>> if (display->platform.BROADWELL) >>>> >>>> I think about 'gen' but then it is overloaded.... >>>> >>>> then I think about 'ip' is worse... >>>> >>>> 'version'? >>>> >>>> 'name'? >>>> >>>> if (display->name.HASWELL)... >>>> >>>> .... >>>> >>>> But well, I like the overall simplification here in general. >>>> Without a better name to suggest, I guess let's just move ahead... >>> >>> One slight concern with the is.foo is whether it complicates finding >>> things with eg. cscope. But I suppose for platforms that doesn't matter >>> all that much. For the has_foo stuff it'd be much more relevant. >> >>It does make finding things harder with cscope and gnu global, but git >>grep for is.FOO is pretty accurate. >> >>> Anyways, can't think of anything particularly elegant myself either, >>> so go ahead I guess. >> >>So I haven't yet. I just still have that slightly uneasy feeling about >>whether this is a good thing or not. That doesn't usually make me shy >>away from things, because you can fix stuff later, but getting this >>wrong causes so much churn everywhere. >> >>The fact that it's not a macro makes it less flexible for future >>changes. The display->is.FOO is somewhat legible, but could be >>better. Would all lowercase make it better? I don't know. >> >>More alternatives? Not elegant for sure, but just alternatives: >> >>- Lowercase names: >> >> if (display->is.rocketlake) > > what I really dislike is a struct named "is". Going full mesa-way would > be slightly better IMO: > > if (display->is_rockelake) > > or > > if (display->platform_rocketlake) > > or > > if (display->platform.rocketlake) Fair enough. >From implementation POV having a sub-struct is easier than not. >> >> Does not help with flexibility or cscope. >> >>- Lowercase macros for display, e.g. is_rocketlake(). >> >> if (is_rocketlake(display)) >> >>- Macros based on just the platform name, e.g. ROCKETLAKE(). >> >> if (ROCKETLAKE(display)) >> >> or change IS_ to something else e.g. PLATFORM_ROCKETLAKE(). >> >> if (PLATFORM_ROCKETLAKE(display)) >> >> But that can get a bit long in some if ladders etc. > > Does it matter much? I think those would be the exception, particularly > because platform checks are kind of rare these days. Well, they're maybe the exception for new platforms, but i915 display does have to deal with a lot of legacy with a lot of platform checks. > grepping for LUNARLAKE in xe reveals only 2 users (+ few workarounds), > because wherever we can we check by graphics/display version rather than > platform. i915 display has only one use of IS_LUNARLAKE(), but there are 1k+ other uses of IS_. Incidentally, this is the reason I'm procrastinating about the change at all. > Then simply using something similar to what we already have in xe, would > be great IMO: > > if (display->platform =3D=3D PLATFORM_LUNARLAKE) > > it may be verbose, but shouldn't be much used to matter in the end. The downside with that is that you can't deal with subplatforms as easily. It becomes if (display->platform =3D=3D PLATFORM_LUNARLAKE || (display->platform =3D=3D PLATFORM_ALDERLAKE_P && display->subplatform =3D=3D SUBPLATFORM_ALDERLAKE_P_ALDERLAKE_N)) or similar. Definitely not a fan. BR, Jani. > > Lucas De Marchi > >> >>- Go through the trouble of making the existing IS_FOO() macros _Generic >> and accept either i915 or display pointer. This does postpone making >> any further changes, but fairly soon there will need to be two sets of >> macros, separate for i915 and display, even though named the same. >> >> Also, the _Generic thing would look up the platform definitions from >> different places, which could be error prone. >> >> >>Yeah, procrastination... >> >> >>BR, >>Jani. >> >> >> >> >>--=20 >>Jani Nikula, Intel --=20 Jani Nikula, Intel