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=-15.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT,USER_IN_DEF_DKIM_WL autolearn=ham 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 DE3E6C43387 for ; Fri, 21 Dec 2018 19:53:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9DB872190A for ; Fri, 21 Dec 2018 19:53:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="bHVbHmaW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391804AbeLUTxX (ORCPT ); Fri, 21 Dec 2018 14:53:23 -0500 Received: from mail-it1-f194.google.com ([209.85.166.194]:38769 "EHLO mail-it1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389508AbeLUTxW (ORCPT ); Fri, 21 Dec 2018 14:53:22 -0500 Received: by mail-it1-f194.google.com with SMTP id h65so8130489ith.3 for ; Fri, 21 Dec 2018 11:53:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=As32mTtNskD5lTtWqwfO6C7FJh2aueD1s9qJC2JV98U=; b=bHVbHmaW1Juvuzwa1CAGwj7gfTF4gLQOctNvPYVowUIMJEN5OB/PEg1ZS7VXe1revb No4kdv1IWWxU8/T0fe6i6vbE+m2RWg7p//Zmj30obbfugbHFPCD+SguuNvOUmKe/ZiHb sE8dw2Kgdo0JpIf6WQZcxRA71nhjoCDzFyLBAqguNjW5P4daOZojRgbdRdXrkjRqe78U yDTSzWIFrmiA3lw0f6CkGItWTsf2wVRaVCtsy48qsgB7xXAtGwHp+KQUCYu7xuJALrYE QXo9j3VSIJSE5OvyGZZdULhi/BrlpgKseQ4YwfKgAXWq/FhQFxVJ4I767sNDpvcqA/qV PzDQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=As32mTtNskD5lTtWqwfO6C7FJh2aueD1s9qJC2JV98U=; b=sbEpuTKzoR/NEqNM9RKOPzE4VmoH3l1P4ZytJhmqNlzbbxd8UwUG082zF62fjvPyrT l100GTJvdKilptXd+O+9XVQlM07dPbDatDFv3vxDYDWvMu+8ehxS8BbAMI6yrXa129BC ExfyhX4IcT7hwpwM0PlQjAR6PesvEcaMejO6tQ91zQuJEqjypFWlmmd7R/pIeNQvt69n TDyX8/yvCG2sjM51TFBNK0pt1Gv8d+gVKkov7EIjbPITGcXSYb98RQXqFkVHyUcMi5vz 35NHrvwJUUf2iLiQn9buGFTy613pInZNlYM8jwBUXDqJxy6qa9BJtHSZaJCs22j2KvaM a64Q== X-Gm-Message-State: AA+aEWY0l385VpbVhT6/Kqt40r+wO7fe0cfttJsmqvcDwklu5d9d0uX+ Na3ckb487S+dNtAGBNvKJcjxOA== X-Google-Smtp-Source: AFSGD/WOAwhhD4okbUzXOjLV9VCFhgcVZNDIfdtWspXAR/RSNNeGB0uqe1nouUKb2XTdp0auq52QKQ== X-Received: by 2002:a02:5ec9:: with SMTP id h192mr2454360jab.112.1545422001652; Fri, 21 Dec 2018 11:53:21 -0800 (PST) Received: from google.com ([2620:15c:183:200:4f03:26b9:1e31:4fda]) by smtp.gmail.com with ESMTPSA id d192sm12053747iog.81.2018.12.21.11.53.20 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 21 Dec 2018 11:53:21 -0800 (PST) Date: Fri, 21 Dec 2018 12:53:18 -0700 From: Ross Zwisler To: Dhinakaran Pandiyan Cc: linux-kernel@vger.kernel.org, Daniel Vetter , David Airlie , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, Jon Flatley Subject: Re: [PATCH] drm/i915/psr: simplify enable_psr handling Message-ID: <20181221195318.GA6483@google.com> References: <20181221172305.195943-1-zwisler@google.com> <147663805b9a1ba7aa3bf4686090af27fbaad040.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <147663805b9a1ba7aa3bf4686090af27fbaad040.camel@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 21, 2018 at 11:23:07AM -0800, Dhinakaran Pandiyan wrote: > On Fri, 2018-12-21 at 10:23 -0700, Ross Zwisler wrote: > > The following commit: > > > > commit 2bdd045e3a30 ("drm/i915/psr: Check if VBT says PSR can be > > enabled.") > > > > added some code with no usable functionality. Regardless of how the > > psr > > default is set up in the BDB_DRIVER_FEATURES section, if the > > enable_psr > > module parameter isn't specified it defaults to 0. > Right, that was intentional and the commit message even makes a note of > it > " Note: The feature currently remains disabled by default for all > platforms irrespective of what VBT says." > > > Anyway, we've enabled the feature by default now and the current code > should take into account the VBT flag if the module parameter is left > to a default value. Please check git://anongit.freedesktop.org/drm-tip > drm-tip. Fair enough. It's a bad pattern to introduce dead code as a placeholder for some future work, though. This code has been in the tree for three major kernel releases (v4.{18,19,20}) without providing any useful functionality.