From patchwork Mon Aug 1 20:03:33 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jesse Barnes X-Patchwork-Id: 1026602 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by demeter2.kernel.org (8.14.4/8.14.4) with ESMTP id p71K3xxN031813 for ; Mon, 1 Aug 2011 20:04:21 GMT Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 35FE79F363 for ; Mon, 1 Aug 2011 13:03:59 -0700 (PDT) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from oproxy7-pub.bluehost.com (oproxy7-pub.bluehost.com [67.222.55.9]) by gabe.freedesktop.org (Postfix) with SMTP id 0B4F59E7D2 for ; Mon, 1 Aug 2011 13:03:40 -0700 (PDT) Received: (qmail 5453 invoked by uid 0); 1 Aug 2011 20:03:40 -0000 Received: from unknown (HELO box514.bluehost.com) (74.220.219.114) by oproxy7.bluehost.com with SMTP; 1 Aug 2011 20:03:40 -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=g2f8VmFx5Vodk+l/NcOb5+xVZzmiIXJ517JOs1dZbjQ=; b=ga2H1mTocu9taNP9Rye6kDuJXbEhyIZ8lkpN0ZwApimBIwUDT+4xTXLMbnlggfEjDEo6+lg845lqMbcsd8Ig+1EOpCP8g50+AwGIq0SkOJacbRv4m+xchZpG5FReYxJb; 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 1QnyiB-0001nY-6d; Mon, 01 Aug 2011 14:03:39 -0600 From: Jesse Barnes To: intel-gfx@lists.freedesktop.org Date: Mon, 1 Aug 2011 13:03:33 -0700 Message-Id: <1312229013-8821-1-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 (demeter2.kernel.org [140.211.167.43]); Mon, 01 Aug 2011 20:04:21 +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. 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..34fbe7b 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 < 10; try++) { + status = I915_READ(ch_ctl); + if ((status & DP_AUX_CH_CTL_SEND_BUSY) == 0) + break; + udelay(100); + } + + if (try == 10) { + WARN(1, "dp_aux_ch not started status 0x%08x\n", + I915_READ(ch_ctl)); return -EBUSY; }