From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757131Ab1I3R5r (ORCPT ); Fri, 30 Sep 2011 13:57:47 -0400 Received: from mail-fx0-f46.google.com ([209.85.161.46]:35361 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754722Ab1I3R5q (ORCPT ); Fri, 30 Sep 2011 13:57:46 -0400 Date: Fri, 30 Sep 2011 19:58:21 +0200 From: Daniel Vetter To: Keith Packard Cc: Daniel Vetter , Dave Airlie , intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, "Barnes, Jesse" Subject: Re: [PATCH 03/21] drm/i915: Remove extra 300ms delay during eDP mode setting Message-ID: <20110930175821.GN2859@phenom.ffwll.local> Mail-Followup-To: Keith Packard , Dave Airlie , intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, "Barnes, Jesse" References: <20110923085243.6e4b7b4c@jbarnes-x220> <1317344993-24945-1-git-send-email-keithp@keithp.com> <1317344993-24945-4-git-send-email-keithp@keithp.com> <20110930162728.GC2859@phenom.ffwll.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: Linux phenom 3.1.0-rc4+ User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 30, 2011 at 10:50:10AM -0700, Keith Packard wrote: > On Fri, 30 Sep 2011 18:27:28 +0200, Daniel Vetter wrote: > > > Can you elaborate a bit why this is no longer needed? Jesse seems to have > > introduced this spefically for edp panels in d209848d61794968. If this > > becomes rendundant due to your panel power sequencing fixes, maybe move it > > down the series? > > The only reason for this delay is to avoid some potential noise on the > screen during mode setting, all of the power sequencing delays are > already correctly managed by the driver. As far as I can tell, we're > trading off the small potential for noise on the screen with an extra > 300ms delay at boot time. > > In the eDP spec, there's a delay listed (T8) between the start of video > data and turning on the backlight. There are no values presented and > the instructions are simply that the source is supposed to wait until > the display is stable. I'm not sure how we'd ever know that the display > is stable. Ok, maybe add the above to paragraphs to the commit msg. Then Reviewed-by: Daniel Vetter -- Daniel Vetter Mail: daniel@ffwll.ch Mobile: +41 (0)79 365 57 48