From patchwork Tue Jul 26 14:50:17 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: cpaul@redhat.com X-Patchwork-Id: 9248291 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id B84AC607D8 for ; Tue, 26 Jul 2016 14:51:14 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A992926A4D for ; Tue, 26 Jul 2016 14:51:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9E45E279E0; Tue, 26 Jul 2016 14:51:14 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3D9A426A4D for ; Tue, 26 Jul 2016 14:51:14 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 834086E51A; Tue, 26 Jul 2016 14:50:50 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by gabe.freedesktop.org (Postfix) with ESMTPS id 18AD06E520; Tue, 26 Jul 2016 14:50:43 +0000 (UTC) Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 82D0BC05AA55; Tue, 26 Jul 2016 14:50:42 +0000 (UTC) Received: from ecstaticemu.bos.redhat.com (dhcp-25-142.bos.redhat.com [10.18.25.142]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u6QEoWeB027140; Tue, 26 Jul 2016 10:50:41 -0400 From: Lyude To: intel-gfx@lists.freedesktop.org, Maarten Lankhorst Subject: [PATCH v3 6/6] drm/i915/skl: Always wait for pipes to update after a flush Date: Tue, 26 Jul 2016 10:50:17 -0400 Message-Id: <1469544617-20003-7-git-send-email-cpaul@redhat.com> In-Reply-To: <1469544617-20003-1-git-send-email-cpaul@redhat.com> References: <1469544617-20003-1-git-send-email-cpaul@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Tue, 26 Jul 2016 14:50:42 +0000 (UTC) Cc: Radhakrishna Sripada , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Hans de Goede , Daniel Vetter , Lyude X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP Unfortunately right now we don't really update watermarks on Skylake properly, since ideally we'd be updating both the ddb allocations, plane properties, and watermarks all in a single go. Until this is fixed however, we can improve things somewhat by adding a vblank wait after the third iteration of pipe flushes, since this forces us to always wait for new ddb allocations to take affect before trying to change them again. Signed-off-by: Lyude Cc: stable@vger.kernel.org Cc: Ville Syrjälä Cc: Daniel Vetter Cc: Radhakrishna Sripada Cc: Hans de Goede Cc: Matt Roper --- drivers/gpu/drm/i915/intel_pm.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 3d48a80..778f760 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -3978,8 +3978,11 @@ static void skl_flush_wm_values(struct drm_i915_private *dev_priv, /* * Third pass: flush the pipes that got more space allocated. * - * We don't need to actively wait for the update here, next vblank - * will just get more DDB space with the correct WM values. + * While the hardware doesn't require to wait for the next vblank here, + * continuing before the pipe finishes updating could result in us + * trying to update the wm values again before the pipe finishes + * updating, which results in the hardware using intermediate wm values + * and subsequently underrunning pipes. */ for_each_intel_crtc(dev, crtc) { if (!crtc->active) @@ -3995,6 +3998,16 @@ static void skl_flush_wm_values(struct drm_i915_private *dev_priv, continue; skl_wm_flush_pipe(dev_priv, pipe, 3); + + /* + * The only time we can get away with not waiting for an update + * is when we just enabled the pipe, e.g. when it doesn't have + * vblanks enabled anyway. + */ + if (drm_crtc_vblank_get(&crtc->base) == 0) { + intel_wait_for_vblank(dev, pipe); + drm_crtc_vblank_put(&crtc->base); + } } }