From patchwork Tue Mar 6 18:37:48 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matt Atwood X-Patchwork-Id: 10262397 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 804B160596 for ; Tue, 6 Mar 2018 18:49:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 697E6290EE for ; Tue, 6 Mar 2018 18:49:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5E8F429132; Tue, 6 Mar 2018 18:49:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 24F53290EE for ; Tue, 6 Mar 2018 18:49:27 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 088B46E24D; Tue, 6 Mar 2018 18:49:25 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTPS id E9CAD6E1F3; Tue, 6 Mar 2018 18:49:22 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Mar 2018 10:49:22 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.47,432,1515484800"; d="scan'208";a="209352410" Received: from dumbledore.jf.intel.com ([10.54.75.158]) by fmsmga006.fm.intel.com with ESMTP; 06 Mar 2018 10:49:22 -0800 From: matthew.s.atwood@intel.com To: dri-devel@lists.freedesktop.org Subject: [PATCH] drm/dp: Correctly mask DP_TRAINING_AUX_RD_INTERVAL values for DP 1.4 Date: Tue, 6 Mar 2018 10:37:48 -0800 Message-Id: <1520361468-32087-1-git-send-email-matthew.s.atwood@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1520029558-12219-1-git-send-email-matthew.s.atwood@intel.com> References: <1520029558-12219-1-git-send-email-matthew.s.atwood@intel.com> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Matt Atwood , intel-gfx@lists.freedesktop.org MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: Matt Atwood DP_TRAINING_AUX_RD_INTERVAL with DP 1.3 spec changed bit scheme from 8 bits to 7 bits in DPCD 0x000e. The 8th bit describes a new feature, for panels that use this new feature, this would cause a wait interval for clock recovery of at least 512 ms, much higher then spec maximum of 16 ms. This behavior is described in table 2-158 of DP 1.4 spec address 0000Eh. To avoid breaking panels that are not spec compliant we now warn on invalid values. V2: commit title/message, masking all 7 bits, warn on out of spec values. Signed-off-by: Matt Atwood Tested-by: Benson Leung Reviewed-by: Rodrigo Vivi --- drivers/gpu/drm/drm_dp_helper.c | 18 ++++++++++++++---- include/drm/drm_dp_helper.h | 1 + 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index adf79be..a718ccc 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -119,18 +119,28 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI EXPORT_SYMBOL(drm_dp_get_adjust_request_pre_emphasis); void drm_dp_link_train_clock_recovery_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) { - if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0) + int rd_interval = dpcd[DP_TRAINING_AUX_RD_INTERVAL] & DP_TRAINING_AUX_RD_MASK; + + if (rd_interval > 4) + DRM_DEBUG_KMS("AUX interval %d, out of range (max 4)", rd_interval); + + if (rd_interval == 0) udelay(100); else - mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4); + mdelay(rd_interval * 4); } EXPORT_SYMBOL(drm_dp_link_train_clock_recovery_delay); void drm_dp_link_train_channel_eq_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) { - if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0) + int rd_interval = dpcd[DP_TRAINING_AUX_RD_INTERVAL] & DP_TRAINING_AUX_RD_MASK; + + if (rd_interval > 4) + DRM_DEBUG_KMS("AUX interval %d, out of range (max 4)", rd_interval); + + if (rd_interval == 0) udelay(400); else - mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4); + mdelay(rd_interval * 4); } EXPORT_SYMBOL(drm_dp_link_train_channel_eq_delay); diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index da58a42..f80acf1 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -118,6 +118,7 @@ # define DP_DPCD_DISPLAY_CONTROL_CAPABLE (1 << 3) /* edp v1.2 or higher */ #define DP_TRAINING_AUX_RD_INTERVAL 0x00e /* XXX 1.2? */ +# define DP_TRAINING_AUX_RD_MASK 0x7F /* 1.3 */ #define DP_ADAPTER_CAP 0x00f /* 1.2 */ # define DP_FORCE_LOAD_SENSE_CAP (1 << 0)