Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753951AbdFOSAp (ORCPT ); Thu, 15 Jun 2017 14:00:45 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:55250 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753041AbdFOSAm (ORCPT ); Thu, 15 Jun 2017 14:00:42 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Maarten Lankhorst , Mahesh Kumar , Matt Roper , Jani Nikula Subject: [PATCH 4.9 107/108] drm/i915: Always recompute watermarks when distrust_bios_wm is set, v2. Date: Thu, 15 Jun 2017 19:53:53 +0200 Message-Id: <20170615175342.222702592@linuxfoundation.org> X-Mailer: git-send-email 2.13.1 In-Reply-To: <20170615175337.190782107@linuxfoundation.org> References: <20170615175337.190782107@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2355 Lines: 66 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Maarten Lankhorst commit 4e3aed844547f63614363a386de126e6304e55fb upstream. On some systems there can be a race condition in which no crtc state is added to the first atomic commit. This results in all crtc's having a null DDB allocation, causing a FIFO underrun on any update until the first modeset. Changes since v1: - Do not take the connection_mutex, this is already done below. Reported-by: Maarten Lankhorst Inspired-by: Mahesh Kumar Signed-off-by: Maarten Lankhorst Fixes: 98d39494d375 ("drm/i915/gen9: Compute DDB allocation at atomic check time (v4)") Cc: Mahesh Kumar Cc: Matt Roper Link: http://patchwork.freedesktop.org/patch/msgid/20170531154236.27180-1-maarten.lankhorst@linux.intel.com Reviewed-by: Mahesh Kumar Reviewed-by: Matt Roper Signed-off-by: Greg Kroah-Hartman (cherry picked from commit 367d73d2806085bb507ab44c1f532640917fd5ca) Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/intel_pm.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -4114,11 +4114,19 @@ skl_compute_wm(struct drm_atomic_state * struct drm_crtc_state *cstate; struct intel_atomic_state *intel_state = to_intel_atomic_state(state); struct skl_wm_values *results = &intel_state->wm_results; + struct drm_device *dev = state->dev; struct skl_pipe_wm *pipe_wm; bool changed = false; int ret, i; /* + * When we distrust bios wm we always need to recompute to set the + * expected DDB allocations for each CRTC. + */ + if (to_i915(dev)->wm.distrust_bios_wm) + changed = true; + + /* * If this transaction isn't actually touching any CRTC's, don't * bother with watermark calculation. Note that if we pass this * test, we're guaranteed to hold at least one CRTC state mutex, @@ -4128,6 +4136,7 @@ skl_compute_wm(struct drm_atomic_state * */ for_each_crtc_in_state(state, crtc, cstate, i) changed = true; + if (!changed) return 0;