From patchwork Tue Mar 31 17:15:00 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Todd Previte X-Patchwork-Id: 6132851 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 9BCEE9F389 for ; Tue, 31 Mar 2015 17:15:26 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 986BB201C0 for ; Tue, 31 Mar 2015 17:15:25 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id 9C7072010B for ; Tue, 31 Mar 2015 17:15:24 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 01AF06E745; Tue, 31 Mar 2015 10:15:23 -0700 (PDT) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mail-pa0-f51.google.com (mail-pa0-f51.google.com [209.85.220.51]) by gabe.freedesktop.org (Postfix) with ESMTP id A0C8F6E743 for ; Tue, 31 Mar 2015 10:15:19 -0700 (PDT) Received: by pacgg7 with SMTP id gg7so25565525pac.0 for ; Tue, 31 Mar 2015 10:15:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=k5wUU3xZwIKMYxvsfxy95bXCGuEBqeP5qR/Aog6uykQ=; b=R4ifOxrMuMtLI9OqkC5IMBQNq3yhfo3iUs0msPuFwu8qwYdbvFjKFBWwo4FkzRyu/R zeI47ZlMd74fddyd3fh9WPm0IHWEBq0kDs+gJYx8GT1m3cRh9WUZAMuLAqYmnPJbeYEC F/zonFW25lPBbGdo/c3yNf/gRWMq7wASi7EoJD25Z7QtGIcPteafZpKet7vB3wBvlzw9 LbvXnXNrCF9S65G336z35f80ayy8RylIPYhX6fZdr6scsHdkQN/nI+JHxeDh1b2wrI8X WDCNS0tBxMT+s0x043x23iyqB2Am2VuZOUJSWlyYGn/B1Co8rlAtM2Knkw3otJSuZ1HS ++jg== X-Received: by 10.68.68.130 with SMTP id w2mr68871425pbt.120.1427822119536; Tue, 31 Mar 2015 10:15:19 -0700 (PDT) Received: from localhost.localdomain (ip70-162-72-208.ph.ph.cox.net. [70.162.72.208]) by mx.google.com with ESMTPSA id ae7sm13897438pac.19.2015.03.31.10.15.18 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 31 Mar 2015 10:15:18 -0700 (PDT) From: Todd Previte To: intel-gfx@lists.freedesktop.org Date: Tue, 31 Mar 2015 10:15:00 -0700 Message-Id: <1427822106-29617-4-git-send-email-tprevite@gmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1427822106-29617-1-git-send-email-tprevite@gmail.com> References: <1427822106-29617-1-git-send-email-tprevite@gmail.com> Subject: [Intel-gfx] [PATCH 3/9] drm/i915: Add a delay in Displayport AUX transactions for compliance testing 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=-4.1 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_MED, T_DKIM_INVALID, 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 The Displayport Link Layer Compliance Testing Specification 1.2 rev 1.1 specifies that repeated AUX transactions after a failure (no response / invalid response) must have a minimum delay of 400us before the resend can occur. Tests 4.2.1.1 and 4.2.1.2 are two tests that require this specifically. V2: - Changed udelay() to usleep_range() V3: - Removed extraneous check for timeout - Updated comment to reflect this change Signed-off-by: Todd Previte --- drivers/gpu/drm/i915/intel_dp.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index ed2f60c..dc87276 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -877,9 +877,15 @@ intel_dp_aux_ch(struct intel_dp *intel_dp, DP_AUX_CH_CTL_TIME_OUT_ERROR | DP_AUX_CH_CTL_RECEIVE_ERROR); - if (status & (DP_AUX_CH_CTL_TIME_OUT_ERROR | - DP_AUX_CH_CTL_RECEIVE_ERROR)) + /* DP CTS 1.2 Core Rev 1.1, 4.2.1.1 & 4.2.1.2 + 400us delay required for errors and timeouts + Timeout errors from the HW already meet this + requirement so skip to next iteration + */ + if (status & DP_AUX_CH_CTL_RECEIVE_ERROR) { + usleep_range(400, 500); continue; + } if (status & DP_AUX_CH_CTL_DONE) break; }