From patchwork Tue Oct 21 10:54:04 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dheeraj Jamwal X-Patchwork-Id: 5119741 Return-Path: X-Original-To: patchwork-ltsi-dev@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id D39DCC11AC for ; Tue, 21 Oct 2014 11:51:04 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 02C5D20121 for ; Tue, 21 Oct 2014 11:51:04 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 32A4A2010F for ; Tue, 21 Oct 2014 11:51:03 +0000 (UTC) Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 56E4C119A; Tue, 21 Oct 2014 11:10:13 +0000 (UTC) X-Original-To: ltsi-dev@lists.linuxfoundation.org Delivered-To: ltsi-dev@mail.linuxfoundation.org Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 0BFB0117C for ; Tue, 21 Oct 2014 11:09:58 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 8B34420203 for ; Tue, 21 Oct 2014 11:09:57 +0000 (UTC) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga101.fm.intel.com with ESMTP; 21 Oct 2014 04:09:26 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,761,1406617200"; d="scan'208";a="617798128" Received: from ubuntu-desktop.png.intel.com ([10.221.122.25]) by fmsmga002.fm.intel.com with ESMTP; 21 Oct 2014 04:09:25 -0700 From: Dheeraj Jamwal To: ltsi-dev@lists.linuxfoundation.org Date: Tue, 21 Oct 2014 18:54:04 +0800 Message-Id: <1413889294-31328-645-git-send-email-dheerajx.s.jamwal@intel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1413889294-31328-1-git-send-email-dheerajx.s.jamwal@intel.com> References: <1413889294-31328-1-git-send-email-dheerajx.s.jamwal@intel.com> X-Spam-Status: No, score=-5.6 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 Subject: [LTSI-dev] [PATCH 0644/1094] drm/i915: fix infinite loop at gen6_update_ring_freq X-BeenThere: ltsi-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: "A list to discuss patches, development, and other things related to the LTSI project" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: ltsi-dev-bounces@lists.linuxfoundation.org Errors-To: ltsi-dev-bounces@lists.linuxfoundation.org X-Virus-Scanned: ClamAV using ClamSMTP From: Paulo Zanoni If I boot my Broadwell machine to X on a system with Mesa Gallium llvmpipe instead of i965, then kill X and try to run pm_pc8.c, when we disable PC8 and call gen6_update_ring_freq(), we will get stuck on an infinite loop because the frequencies are zero and the variables are unsigned. This happens because we never ran any batch, so we did not enable RC6, so the variables are zero. If I run gem_exec_nop before running pm_pc8, everything works as expected because gem_exec_nop makes RC6 be enabled. This commit should prevent the infinite loop, which IMHO is already a good reason to be merged, but it is not the proper fix to the "RC6 is not being enabled" problem. Signed-off-by: Paulo Zanoni Signed-off-by: Daniel Vetter (cherry picked from commit 4b28a1f3ef55a3b0b68dbab1fe6dbaf18e186710) Signed-off-by: Dheeraj Jamwal --- drivers/gpu/drm/i915/intel_pm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 52ddca0..540fec2 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -3537,7 +3537,8 @@ void gen6_update_ring_freq(struct drm_device *dev) * to use for memory access. We do this by specifying the IA frequency * the PCU should use as a reference to determine the ring frequency. */ - for (gpu_freq = dev_priv->rps.max_freq_softlimit; gpu_freq >= dev_priv->rps.min_freq_softlimit; + for (gpu_freq = dev_priv->rps.max_freq_softlimit; + gpu_freq >= dev_priv->rps.min_freq_softlimit && gpu_freq != 0; gpu_freq--) { int diff = dev_priv->rps.max_freq_softlimit - gpu_freq; unsigned int ia_freq = 0, ring_freq = 0;