From patchwork Wed Apr 29 06:17:39 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mika Kahola X-Patchwork-Id: 6293831 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 6A4999F1C2 for ; Wed, 29 Apr 2015 06:17:47 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id AED0420254 for ; Wed, 29 Apr 2015 06:17:42 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id 6727F2021A for ; Wed, 29 Apr 2015 06:17:32 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 93ADD6E26C; Tue, 28 Apr 2015 23:17:30 -0700 (PDT) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by gabe.freedesktop.org (Postfix) with ESMTP id 459026E16E for ; Tue, 28 Apr 2015 23:17:29 -0700 (PDT) Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga101.jf.intel.com with ESMTP; 28 Apr 2015 23:17:29 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.11,669,1422950400"; d="scan'208";a="487027644" Received: from sorvi.fi.intel.com ([10.237.72.165]) by FMSMGA003.fm.intel.com with ESMTP; 28 Apr 2015 23:17:28 -0700 From: Mika Kahola To: intel-gfx@lists.freedesktop.org Date: Wed, 29 Apr 2015 09:17:39 +0300 Message-Id: <1430288260-23718-2-git-send-email-mika.kahola@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1430288260-23718-1-git-send-email-mika.kahola@intel.com> References: <1430288260-23718-1-git-send-email-mika.kahola@intel.com> Subject: [Intel-gfx] [PATCH v4 1/2] drm/i915: DP link training optimization 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 This is a first of series patches that optimize DP link training. The first patch is for eDP only where we reuse the previously trained link training values from cache i.e. voltage swing and pre-emphasis levels. In case we are not able to train the link by reusing the known values, the link training parameters are set to zero and training is restarted. V2: - flag that indicates if DP link is trained and valid renamed from 'link_trained' to 'train_set_valid' - removed routine 'intel_dp_reuse_link_train' V3: - rebased against the latest drm-intel-nightly V4: - removed HPD long pulse handling for eDP case to clear the flag that indicates to reuse the current link training parameters. (based on Sivakumar's comment) Signed-off-by: Mika Kahola Reviewed-by: Sivakumar Thulasimani --- drivers/gpu/drm/i915/intel_dp.c | 27 ++++++++++++++++++++++++--- drivers/gpu/drm/i915/intel_drv.h | 1 + 2 files changed, 25 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 937ba31..e0b35cb 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -3547,7 +3547,8 @@ static bool intel_dp_reset_link_train(struct intel_dp *intel_dp, uint32_t *DP, uint8_t dp_train_pat) { - memset(intel_dp->train_set, 0, sizeof(intel_dp->train_set)); + if (!intel_dp->train_set_valid) + memset(intel_dp->train_set, 0, sizeof(intel_dp->train_set)); intel_dp_set_signal_levels(intel_dp, DP); return intel_dp_set_link_train(intel_dp, DP, dp_train_pat); } @@ -3660,6 +3661,23 @@ intel_dp_start_link_train(struct intel_dp *intel_dp) break; } + /* + * if we used previously trained voltage and pre-emphasis values + * and we don't get clock recovery, reset link training values + */ + if (intel_dp->train_set_valid) { + DRM_DEBUG_KMS("clock recovery not ok, reset"); + /* clear the flag as we are not reusing train set */ + intel_dp->train_set_valid = false; + if (!intel_dp_reset_link_train(intel_dp, &DP, + DP_TRAINING_PATTERN_1 | + DP_LINK_SCRAMBLING_DISABLE)) { + DRM_ERROR("failed to enable link training\n"); + return; + } + continue; + } + /* Check to see if we've tried the max voltage */ for (i = 0; i < intel_dp->lane_count; i++) if ((intel_dp->train_set[i] & DP_TRAIN_MAX_SWING_REACHED) == 0) @@ -3737,6 +3755,7 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp) /* Make sure clock is still ok */ if (!drm_dp_clock_recovery_ok(link_status, intel_dp->lane_count)) { + intel_dp->train_set_valid = false; intel_dp_start_link_train(intel_dp); intel_dp_set_link_train(intel_dp, &DP, training_pattern | @@ -3752,6 +3771,7 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp) /* Try 5 times, then try clock recovery if that fails */ if (tries > 5) { + intel_dp->train_set_valid = false; intel_dp_start_link_train(intel_dp); intel_dp_set_link_train(intel_dp, &DP, training_pattern | @@ -3773,9 +3793,10 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp) intel_dp->DP = DP; - if (channel_eq) + if (channel_eq) { + intel_dp->train_set_valid = is_edp(intel_dp); DRM_DEBUG_KMS("Channel EQ done. DP Training successful\n"); - + } } void intel_dp_stop_link_train(struct intel_dp *intel_dp) diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h index 43fe003..94197bd 100644 --- a/drivers/gpu/drm/i915/intel_drv.h +++ b/drivers/gpu/drm/i915/intel_drv.h @@ -736,6 +736,7 @@ struct intel_dp { bool has_aux_irq, int send_bytes, uint32_t aux_clock_divider); + bool train_set_valid; /* Displayport compliance testing */ unsigned long compliance_test_type;