From mboxrd@z Thu Jan 1 00:00:00 1970 From: Todd Previte Subject: [PATCH 2/6] drm/i915: Add a delay in Displayport AUX transactions for compliance testing Date: Tue, 24 Jun 2014 15:12:50 -0700 Message-ID: <1403647974-42377-3-git-send-email-tprevite@gmail.com> References: <1403647974-42377-1-git-send-email-tprevite@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pb0-f46.google.com (mail-pb0-f46.google.com [209.85.160.46]) by gabe.freedesktop.org (Postfix) with ESMTP id 6359E6E5B7 for ; Tue, 24 Jun 2014 15:13:32 -0700 (PDT) Received: by mail-pb0-f46.google.com with SMTP id md12so800052pbc.33 for ; Tue, 24 Jun 2014 15:13:32 -0700 (PDT) In-Reply-To: <1403647974-42377-1-git-send-email-tprevite@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org Several compliance tests require that follow-up AUX transactions (after a failure or no response) are not resent sooner than 400us later. Add a 400us delay to the response time of any failed transaction to account for this. Signed-off-by: Todd Previte --- drivers/gpu/drm/i915/intel_dp.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 3bd1780..43fcabe 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -561,8 +561,12 @@ intel_dp_aux_ch(struct intel_dp *intel_dp, DP_AUX_CH_CTL_RECEIVE_ERROR); if (status & (DP_AUX_CH_CTL_TIME_OUT_ERROR | - DP_AUX_CH_CTL_RECEIVE_ERROR)) + DP_AUX_CH_CTL_RECEIVE_ERROR)) { + /* 400us delay between transactions for errors/timeouts + required for DP compliance testing */ + udelay(400); continue; + } if (status & DP_AUX_CH_CTL_DONE) break; } -- 1.9.1