From patchwork Thu May 7 17:38:49 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Lespiau, Damien" X-Patchwork-Id: 6359941 Return-Path: X-Original-To: patchwork-intel-gfx@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 9849C9F1C2 for ; Thu, 7 May 2015 17:39:06 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id D21DD203AA for ; Thu, 7 May 2015 17:39:05 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id 1386B20376 for ; Thu, 7 May 2015 17:39:05 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A77EE72139; Thu, 7 May 2015 10:39:04 -0700 (PDT) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by gabe.freedesktop.org (Postfix) with ESMTP id AFB266E886 for ; Thu, 7 May 2015 10:39:02 -0700 (PDT) Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP; 07 May 2015 10:39:01 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,384,1427785200"; d="scan'208";a="706830543" Received: from rpeel-mobl3.ger.corp.intel.com (HELO strange.ger.corp.intel.com) ([10.252.14.166]) by fmsmga001.fm.intel.com with ESMTP; 07 May 2015 10:39:01 -0700 From: Damien Lespiau To: intel-gfx@lists.freedesktop.org Date: Thu, 7 May 2015 18:38:49 +0100 Message-Id: <1431020329-11414-14-git-send-email-damien.lespiau@intel.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1431020329-11414-1-git-send-email-damien.lespiau@intel.com> References: <1431020329-11414-1-git-send-email-damien.lespiau@intel.com> Subject: [Intel-gfx] [PATCH 13/13] drm/i915/skl: Prefer even dividers for SKL DPLLs X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Currently, if an odd divider improves the deviation (minimizes it), we take that divider. The recommendation is to prefer even dividers. Signed-off-by: Damien Lespiau Tested-By: Intel Graphics QA PRTS (Patch Regression Test System Contact: shuang.he@intel.com) --- drivers/gpu/drm/i915/intel_ddi.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c index 381a8c9..54344c3 100644 --- a/drivers/gpu/drm/i915/intel_ddi.c +++ b/drivers/gpu/drm/i915/intel_ddi.c @@ -1308,6 +1308,13 @@ skl_ddi_calculate_wrpll(int clock /* in Hz */, dco_freq, p); } + + /* + * If a solution is found with an even divider, prefer + * this one. + */ + if (d == 0 && ctx.p) + break; } }