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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 EB991C07E96 for ; Tue, 6 Jul 2021 23:44:38 +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 9AA52619C6 for ; Tue, 6 Jul 2021 23:44:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9AA52619C6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4C0046E5C8; Tue, 6 Jul 2021 23:44:38 +0000 (UTC) Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by gabe.freedesktop.org (Postfix) with ESMTPS id 84C076E5C8 for ; Tue, 6 Jul 2021 23:44:36 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10037"; a="196379846" X-IronPort-AV: E=Sophos;i="5.83,330,1616482800"; d="scan'208";a="196379846" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Jul 2021 16:44:32 -0700 X-IronPort-AV: E=Sophos;i="5.83,330,1616482800"; d="scan'208";a="497368161" Received: from asolispe-mobl1.amr.corp.intel.com (HELO ldmartin-desk2) ([10.254.41.174]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Jul 2021 16:44:31 -0700 Date: Tue, 6 Jul 2021 16:44:30 -0700 From: Lucas De Marchi To: Joonas Lahtinen Message-ID: <20210706234430.nm64jerbt3kkoeue@ldmartin-desk2> X-Patchwork-Hint: comment References: <20201027044618.719064-1-lucas.demarchi@intel.com> <20201027044618.719064-3-lucas.demarchi@intel.com> <160448371454.8986.12904696092648361290@jlahtine-mobl.ger.corp.intel.com> <20201105010422.l2mum5gep7dxva5f@ldmartin-desk1.jf.intel.com> <160456334665.5393.4671076622521791518@jlahtine-mobl.ger.corp.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <160456334665.5393.4671076622521791518@jlahtine-mobl.ger.corp.intel.com> Subject: Re: [Intel-gfx] [PATCH 3/3] drm/i915: remove some debug-only registers from MCHBAR X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Thu, Nov 05, 2020 at 10:02:27AM +0200, Joonas Lahtinen wrote: >Quoting Lucas De Marchi (2020-11-05 03:04:22) >> On Wed, Nov 04, 2020 at 11:55:15AM +0200, Joonas Lahtinen wrote: >> >Quoting Lucas De Marchi (2020-10-27 06:46:18) >> >> GT_PERF_STATUS and RP_STATE_LIMITS were added a long time ago in >> >> commit 3b8d8d91d51c ("drm/i915: dynamic render p-state support for Sandy >> >> Bridge"). Other than printing their values in debugfs we don't do >> >> anything with them. There's not much useful information in them. These >> >> registers may change location in future platforms, but instead of adding >> >> new locations, it's simpler to just remove them. >> > >> >This code seems to have been updated for Gen9LP, so that would indicate >> >the debugging information is useful, right? The value is even decoded, not >> >simply dumped as most registers. So I would be hesitant to drop it for >> >not being useful. >> >> but just updating the register in itself for a new gen doesn't mean it's >> actually useful... the commit message where this happened is pretty >> vague: 350405623ff3 ("drm/i915: Update rps frequencies for BXT") >> >> My first reaction would be to do the same if the register had moved or >> if it ceased to exist in a new platform. Talking with Matt Roper some >> time ago we arrived to the conclusion that just printing these values is >> not giving us much benefit and it could very well be accomplished by >> intel_reg. >> >> So answering the question: is it really useful as is? IMO, no. > >A quick discussion on #intel-gfx seems to indicate it was used for >bug triaging in the past year. So that would indicate it is still >useful to include. getting back to this as we are trying to upstream XeHP-SDV that doesn't have access to the MCHBAR. So do you think we should just make it conditional instead of removing? I'm still on the side that this additional code doesn't bring much value and could be replaced by intel-reg. > >So let's not remove it. > >> >The second question is why we have a huge block of 1-to-1 duplicated >> >code in there. Has there been an incorrect merge or some transition has >> >been left mid-way? >> >> not a bad merge, no. It seems to be to preserve the previous file >> location since now it moved to be inside a gt dir. Long term I think >> this is bad both because of the code duplication and because it's easy >> to update one and forget the other. > >I started a discussion in the thread of the original patch which called >to move code but left the old code in place too, effectively copying it. > >When this path was written and such code duplication noticed, would have >been good to highlight or address the code duplication. yes, but it doesn't mean there will be an action regarding that, as can be noticed since that duplication is still there today and this patch applies cleanly :-/... and they had slightly different changes according to git log -L:frequency_show:drivers/gpu/drm/i915/gt/debugfs_gt_pm.c \ -L:i915_frequency_info:drivers/gpu/drm/i915/i915_debugfs.c Lucas De Marchi _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx