From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ross Zwisler Subject: Re: [PATCH] drm/i915/psr: simplify enable_psr handling Date: Fri, 21 Dec 2018 12:53:18 -0700 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 Return-path: Content-Disposition: inline In-Reply-To: <147663805b9a1ba7aa3bf4686090af27fbaad040.camel@intel.com> Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: dri-devel@lists.freedesktop.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.