From patchwork Mon Apr 22 14:23:50 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?b?VmlsbGUgU3lyasOkbMOk?= X-Patchwork-Id: 2472201 Return-Path: X-Original-To: patchwork-intel-gfx@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by patchwork2.kernel.org (Postfix) with ESMTP id 0928BDF23A for ; Mon, 22 Apr 2013 14:25:35 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id ECE01E6830 for ; Mon, 22 Apr 2013 07:25:34 -0700 (PDT) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga03.intel.com (mga03.intel.com [143.182.124.21]) by gabe.freedesktop.org (Postfix) with ESMTP id 8171DE6836 for ; Mon, 22 Apr 2013 07:23:53 -0700 (PDT) Received: from azsmga001.ch.intel.com ([10.2.17.19]) by azsmga101.ch.intel.com with ESMTP; 22 Apr 2013 07:23:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,526,1363158000"; d="scan'208";a="289791073" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.168]) by azsmga001.ch.intel.com with SMTP; 22 Apr 2013 07:23:51 -0700 Received: by stinkbox (sSMTP sendmail emulation); Mon, 22 Apr 2013 17:23:50 +0300 From: ville.syrjala@linux.intel.com To: intel-gfx@lists.freedesktop.org Date: Mon, 22 Apr 2013 17:23:50 +0300 Message-Id: <1366640630-3834-1-git-send-email-ville.syrjala@linux.intel.com> X-Mailer: git-send-email 1.8.1.5 MIME-Version: 1.0 Subject: [Intel-gfx] [RFC][PATCH] drm/i915: Make data/link N value power of two X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+patchwork-intel-gfx=patchwork.kernel.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+patchwork-intel-gfx=patchwork.kernel.org@lists.freedesktop.org From: Ville Syrjälä The BIOS uses power of two values for the data/link N value. Follow suit to make the Zotac DP to dual-HDMI dongle work. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49402 Signed-off-by: Ville Syrjälä Acked-by: Chris Wilson --- Warning: I've only tested this with the Zotac dongle hooked to my 1080p Samsumg telly. Whether or not it works with other displays is an open question. drivers/gpu/drm/i915/intel_display.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 74156e2..fea9c99 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -4151,18 +4151,29 @@ intel_reduce_ratio(uint32_t *num, uint32_t *den) } } +static void compute_m_n(int m, int n, uint32_t *ret_m, uint32_t *ret_n) +{ + if (n >= 1 << 23) + *ret_n = 1 << 23; + else + *ret_n = roundup_pow_of_two(n); + *ret_m = div_u64((uint64_t) m * *ret_n, n); + intel_reduce_ratio(ret_m, ret_n); +} + void intel_link_compute_m_n(int bits_per_pixel, int nlanes, int pixel_clock, int link_clock, struct intel_link_m_n *m_n) { m_n->tu = 64; - m_n->gmch_m = bits_per_pixel * pixel_clock; - m_n->gmch_n = link_clock * nlanes * 8; - intel_reduce_ratio(&m_n->gmch_m, &m_n->gmch_n); - m_n->link_m = pixel_clock; - m_n->link_n = link_clock; - intel_reduce_ratio(&m_n->link_m, &m_n->link_n); + + compute_m_n(bits_per_pixel * pixel_clock, + link_clock * nlanes * 8, + &m_n->gmch_m, &m_n->gmch_n); + + compute_m_n(pixel_clock, link_clock, + &m_n->link_m, &m_n->link_n); } static inline bool intel_panel_use_ssc(struct drm_i915_private *dev_priv)