From patchwork Mon Aug 1 21:14:35 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jesse Barnes X-Patchwork-Id: 1026792 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by demeter1.kernel.org (8.14.4/8.14.4) with ESMTP id p71LF77d006484 for ; Mon, 1 Aug 2011 21:15:28 GMT Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 003549F36E for ; Mon, 1 Aug 2011 14:15:06 -0700 (PDT) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from oproxy3-pub.bluehost.com (oproxy3-pub.bluehost.com [69.89.21.8]) by gabe.freedesktop.org (Postfix) with SMTP id D74949E997 for ; Mon, 1 Aug 2011 14:14:42 -0700 (PDT) Received: (qmail 12305 invoked by uid 0); 1 Aug 2011 21:14:42 -0000 Received: from unknown (HELO box514.bluehost.com) (74.220.219.114) by oproxy3.bluehost.com with SMTP; 1 Aug 2011 21:14:42 -0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=virtuousgeek.org; s=default; h=Message-Id:Date:Subject:Cc:To:From; bh=PGT+m3qMGsIyutsV/AQA44SODO/HFHnhaKVrn2VyXSU=; b=pfoBPk3M9OO4ImWWtM4T/NhpFsYwxLc/OlQvfYb0EG0bxyIsC+49fh1Jay0sphbi/lmmqjRlnJ7K+pscXuzHDXqDjQ57y8AN022F8efiRSNeT5Hn4oCfbnude+C2tz84; Received: from c-67-161-37-189.hsd1.ca.comcast.net ([67.161.37.189] helo=localhost.localdomain) by box514.bluehost.com with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.69) (envelope-from ) id 1Qnzov-0004Gt-K7; Mon, 01 Aug 2011 15:14:41 -0600 From: Jesse Barnes To: intel-gfx@lists.freedesktop.org Date: Mon, 1 Aug 2011 14:14:35 -0700 Message-Id: <1312233275-10843-1-git-send-email-jbarnes@virtuousgeek.org> X-Mailer: git-send-email 1.7.4.1 X-Identified-User: {10642:box514.bluehost.com:virtuous:virtuousgeek.org} {sentby:smtp auth 67.161.37.189 authed with jbarnes@virtuousgeek.org} Subject: [Intel-gfx] [PATCH] drm/i915/dp: wait for previous AUX channel activity to clear X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.11 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: intel-gfx-bounces+patchwork-intel-gfx=patchwork.kernel.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+patchwork-intel-gfx=patchwork.kernel.org@lists.freedesktop.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Mon, 01 Aug 2011 21:15:28 +0000 (UTC) Before initiating a new read or write on the DP AUX channel, wait for any outstanding activity to complete. This may happen during normal retry behavior. If the wait fails (i.e. after 1ms the AUX channel is still busy) dump a backtrace to make the caller easier to spot. v2: use msleep instead, and timeout after 3ms (only ever saw 1 retry with msleep in testing) Fixes https://bugs.freedesktop.org/show_bug.cgi?id=38136. Signed-off-by: Jesse Barnes --- drivers/gpu/drm/i915/intel_dp.c | 14 +++++++++++--- 1 files changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 4493641..de570ce 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -315,9 +315,17 @@ intel_dp_aux_ch(struct intel_dp *intel_dp, else precharge = 5; - if (I915_READ(ch_ctl) & DP_AUX_CH_CTL_SEND_BUSY) { - DRM_ERROR("dp_aux_ch not started status 0x%08x\n", - I915_READ(ch_ctl)); + /* Try to wait for any previous AUX channel activity */ + for (try = 0; try < 3; try++) { + status = I915_READ(ch_ctl); + if ((status & DP_AUX_CH_CTL_SEND_BUSY) == 0) + break; + msleep(1); + } + + if (try == 10) { + WARN(1, "dp_aux_ch not started status 0x%08x\n", + I915_READ(ch_ctl)); return -EBUSY; }