From patchwork Sat Nov 21 00:46:29 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Vivi, Rodrigo" X-Patchwork-Id: 7672951 Return-Path: X-Original-To: patchwork-dri-devel@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 8B9A49F1C2 for ; Sat, 21 Nov 2015 00:46:03 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B607720588 for ; Sat, 21 Nov 2015 00:46:02 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id DF8922056D for ; Sat, 21 Nov 2015 00:46:01 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B18316EB6C; Fri, 20 Nov 2015 16:45:53 -0800 (PST) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by gabe.freedesktop.org (Postfix) with ESMTP id 1E7306EB72; Fri, 20 Nov 2015 16:45:51 -0800 (PST) Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga103.jf.intel.com with ESMTP; 20 Nov 2015 16:45:50 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,325,1444719600"; d="scan'208";a="825676452" Received: from rdvivi-hillsboro.jf.intel.com ([10.7.196.156]) by orsmga001.jf.intel.com with ESMTP; 20 Nov 2015 16:45:49 -0800 From: Rodrigo Vivi To: intel-gfx@lists.freedesktop.org Subject: [PATCH 7/8] drm/i915: Fix random aux transactions failures. Date: Fri, 20 Nov 2015 16:46:29 -0800 Message-Id: <1448066790-19591-8-git-send-email-rodrigo.vivi@intel.com> X-Mailer: git-send-email 2.4.3 In-Reply-To: <1448066790-19591-1-git-send-email-rodrigo.vivi@intel.com> References: <1448066790-19591-1-git-send-email-rodrigo.vivi@intel.com> Cc: Jani Nikula , Daniel Vetter , dri-devel@lists.freedesktop.org, Rodrigo Vivi X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Spam-Status: No, score=-4.8 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, 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 Mainly aux communications on sink_crc were failing a lot randomly on recent platforms. The first solution was to try to use intel_dp_dpcd_read_wake, but then it was suggested to move retries to drm level. Since drm level was already taking care of retries and didn't want to through random retries on that level the second solution was to put the retries at aux_transfer layer what was nacked. So I realized we had so many retries in different places and started to organize that a bit. During this organization I noticed that we weren't handing at all the case were the message size was zeroed. And this was exactly the case that was affecting sink_crc. Also we weren't respect BSPec who says this size message = 0 or > 20 are forbidden. It is a fact that we still have no clue why we are getting this forbidden value there. But anyway we need to handle that for now so we return -EBUSY and drm level takes care of the retries that are already in place. Cc: Jani Nikula Cc: Daniel Vetter Signed-off-by: Rodrigo Vivi --- drivers/gpu/drm/i915/intel_dp.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 35048d6..c87e937 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -905,6 +905,17 @@ done: /* Unload any bytes sent back from the other side */ recv_bytes = ((status & DP_AUX_CH_CTL_MESSAGE_SIZE_MASK) >> DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT); + + /* + * By BSpec: "Message sizes of 0 or >20 are not allowed." + * We have no idea of what happened so we return -EBUSY so + * drm layer takes care for the necessary retries. + */ + if (recv_bytes == 0 || recv_bytes > 20) { + ret = -EBUSY; + goto out; + } + if (recv_bytes > recv_size) recv_bytes = recv_size;