From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753322AbcH2Qbd (ORCPT ); Mon, 29 Aug 2016 12:31:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42106 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751140AbcH2Qbc (ORCPT ); Mon, 29 Aug 2016 12:31:32 -0400 From: Lyude To: Jani Nikula Cc: Lyude , Maarten Lankhorst , Daniel Vetter , David Airlie , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH v3] drm/i915/skl: Don't try to update plane watermarks if they haven't changed Date: Mon, 29 Aug 2016 12:31:27 -0400 Message-Id: <1472488288-27280-1-git-send-email-cpaul@redhat.com> In-Reply-To: <871t17ipah.fsf@intel.com> References: <871t17ipah.fsf@intel.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Mon, 29 Aug 2016 16:31:31 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org i915 sometimes needs to disable planes in the middle of an atomic commit, and then reenable them later in the same commit. Because of this, we can't make the assumption that the state of the plane actually changed. Since the state of the plane hasn't actually changed, neither have it's watermarks. And if the watermarks hasn't changed then we haven't populated skl_results with anything, which means we'll end up zeroing out a plane's watermarks in the middle of the atomic commit without restoring them later. Simple reproduction recipe: - Get a SKL laptop, launch any kind of X session - Get two extra monitors - Keep hotplugging both displays (so that the display configuration jumps from 1 active pipe to 3 active pipes and back) - Eventually underrun Changes since v1: - Fix incorrect use of "it's" Changes since v2: - Add reproduction recipe Signed-off-by: Lyude Cc: Maarten Lankhorst Fixes: 62e0fb880123 ("drm/i915/skl: Update plane watermarks atomically during plane updates") Signed-off-by: Lyude --- drivers/gpu/drm/i915/intel_display.c | 7 ++++++- drivers/gpu/drm/i915/intel_sprite.c | 9 +++++++-- 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index e4e6141..13e47a7 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -3448,7 +3448,12 @@ static void skylake_disable_primary_plane(struct drm_plane *primary, struct intel_crtc *intel_crtc = to_intel_crtc(crtc); int pipe = intel_crtc->pipe; - skl_write_plane_wm(intel_crtc, &dev_priv->wm.skl_results, 0); + /* + * We only populate skl_results on watermark updates, and if the + * plane's visiblity isn't actually changing neither is its watermarks. + */ + if (!crtc->primary->state->visible) + skl_write_plane_wm(intel_crtc, &dev_priv->wm.skl_results, 0); I915_WRITE(PLANE_CTL(pipe, 0), 0); I915_WRITE(PLANE_SURF(pipe, 0), 0); diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c index 0df783a..73a521f 100644 --- a/drivers/gpu/drm/i915/intel_sprite.c +++ b/drivers/gpu/drm/i915/intel_sprite.c @@ -292,8 +292,13 @@ skl_disable_plane(struct drm_plane *dplane, struct drm_crtc *crtc) const int pipe = intel_plane->pipe; const int plane = intel_plane->plane + 1; - skl_write_plane_wm(to_intel_crtc(crtc), &dev_priv->wm.skl_results, - plane); + /* + * We only populate skl_results on watermark updates, and if the + * plane's visiblity isn't actually changing neither is its watermarks. + */ + if (!dplane->state->visible) + skl_write_plane_wm(to_intel_crtc(crtc), + &dev_priv->wm.skl_results, plane); I915_WRITE(PLANE_CTL(pipe, plane), 0); -- 2.7.4