From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jani Nikula Subject: [PATCH] drm/i915: use lower aux clock divider on non-ULT HSW Date: Mon, 8 Apr 2013 23:00:58 +0300 Message-ID: <1365451258-25493-1-git-send-email-jani.nikula@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTP id 093D5E5EAD for ; Mon, 8 Apr 2013 13:02:24 -0700 (PDT) List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: intel-gfx@lists.freedesktop.org Cc: jani.nikula@intel.com List-Id: intel-gfx@lists.freedesktop.org Workaround to avoid intermittent aux channel failures, per spec change. Signed-off-by: Jani Nikula --- Untested. --- drivers/gpu/drm/i915/intel_dp.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 482b5e5..5fec183 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -344,7 +344,10 @@ intel_dp_aux_ch(struct intel_dp *intel_dp, * Note that PCH attached eDP panels should use a 125MHz input * clock divider. */ - if (is_cpu_edp(intel_dp)) { + if (dev_priv->pch_id == INTEL_PCH_LPT_DEVICE_ID_TYPE) { + /* Workaround for non-ULT HSW */ + aux_clock_divider = 74; + } else if (is_cpu_edp(intel_dp)) { if (HAS_DDI(dev)) aux_clock_divider = intel_ddi_get_cdclk_freq(dev_priv) >> 1; else if (IS_VALLEYVIEW(dev)) -- 1.7.10.4