From patchwork Mon Jun 3 16:56:10 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Helen Mae Koike Fornazier X-Patchwork-Id: 10973365 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 242E26C5 for ; Mon, 3 Jun 2019 16:57:06 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0F24628684 for ; Mon, 3 Jun 2019 16:57:06 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 023BE2873C; Mon, 3 Jun 2019 16:57:05 +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=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 800B328684 for ; Mon, 3 Jun 2019 16:57:05 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 65D01892C0; Mon, 3 Jun 2019 16:57:04 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by gabe.freedesktop.org (Postfix) with ESMTPS id BD25E89258; Mon, 3 Jun 2019 16:57:02 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: koike) with ESMTPSA id 1DD31284FB7 From: Helen Koike To: dri-devel@lists.freedesktop.org, nicholas.kazlauskas@amd.com Subject: [PATCH v4 5/5] drm: don't block fb changes for async plane updates Date: Mon, 3 Jun 2019 13:56:10 -0300 Message-Id: <20190603165610.24614-6-helen.koike@collabora.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190603165610.24614-1-helen.koike@collabora.com> References: <20190603165610.24614-1-helen.koike@collabora.com> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sean Paul , David Airlie , daniel.vetter@ffwll.ch, linux-kernel@vger.kernel.org, kernel@collabora.com, Maxime Ripard , amd-gfx@lists.freedesktop.org, linux-rockchip@lists.infradead.org, linux-arm-msm@vger.kernel.org, Helen Koike , Sean Paul , linux-arm-kernel@lists.infradead.org, =?utf-8?q?St=C3=A9phane_Marchesin?= , stable@vger.kernel.org, Tomasz Figa , boris.brezillon@collabora.com, freedreno@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP In the case of a normal sync update, the preparation of framebuffers (be it calling drm_atomic_helper_prepare_planes() or doing setups with drm_framebuffer_get()) are performed in the new_state and the respective cleanups are performed in the old_state. In the case of async updates, the preparation is also done in the new_state but the cleanups are done in the new_state (because updates are performed in place, i.e. in the current state). The current code blocks async udpates when the fb is changed, turning async updates into sync updates, slowing down cursor updates and introducing regressions in igt tests with errors of type: "CRITICAL: completed 97 cursor updated in a period of 30 flips, we expect to complete approximately 15360 updates, with the threshold set at 7680" Fb changes in async updates were prevented to avoid the following scenario: - Async update, oldfb = NULL, newfb = fb1, prepare fb1, cleanup fb1 - Async update, oldfb = fb1, newfb = fb2, prepare fb2, cleanup fb2 - Non-async commit, oldfb = fb2, newfb = fb1, prepare fb1, cleanup fb2 (wrong) Where we have a single call to prepare fb2 but double cleanup call to fb2. To solve the above problems, instead of blocking async fb changes, we place the old framebuffer in the new_state object, so when the code performs cleanups in the new_state it will cleanup the old_fb and we will have the following scenario instead: - Async update, oldfb = NULL, newfb = fb1, prepare fb1, no cleanup - Async update, oldfb = fb1, newfb = fb2, prepare fb2, cleanup fb1 - Non-async commit, oldfb = fb2, newfb = fb1, prepare fb1, cleanup fb2 Where calls to prepare/cleanup are balanced. Cc: # v4.14+ Fixes: 25dc194b34dd ("drm: Block fb changes for async plane updates") Suggested-by: Boris Brezillon Signed-off-by: Helen Koike Reviewed-by: Boris Brezillon Reviewed-by: Nicholas Kazlauskas --- Changes in v4: - update docs in atomic_async_update callback Changes in v3: - Add Reviewed-by tags - Add TODO in drm_atomic_helper_async_commit() Changes in v2: - Change the order of the patch in the series, add this as the last one. - Add documentation - s/ballanced/balanced drivers/gpu/drm/drm_atomic_helper.c | 22 ++++++++++++---------- include/drm/drm_modeset_helper_vtables.h | 8 ++++++++ 2 files changed, 20 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index acf993cb8e52..ac81d8440b40 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -1610,15 +1610,6 @@ int drm_atomic_helper_async_check(struct drm_device *dev, old_plane_state->crtc != new_plane_state->crtc) return -EINVAL; - /* - * FIXME: Since prepare_fb and cleanup_fb are always called on - * the new_plane_state for async updates we need to block framebuffer - * changes. This prevents use of a fb that's been cleaned up and - * double cleanups from occuring. - */ - if (old_plane_state->fb != new_plane_state->fb) - return -EINVAL; - funcs = plane->helper_private; if (!funcs->atomic_async_update) return -EINVAL; @@ -1649,6 +1640,8 @@ EXPORT_SYMBOL(drm_atomic_helper_async_check); * drm_atomic_async_check() succeeds. Async commits are not supposed to swap * the states like normal sync commits, but just do in-place changes on the * current state. + * + * TODO: Implement full swap instead of doing in-place changes. */ void drm_atomic_helper_async_commit(struct drm_device *dev, struct drm_atomic_state *state) @@ -1659,6 +1652,9 @@ void drm_atomic_helper_async_commit(struct drm_device *dev, int i; for_each_new_plane_in_state(state, plane, plane_state, i) { + struct drm_framebuffer *new_fb = plane_state->fb; + struct drm_framebuffer *old_fb = plane->state->fb; + funcs = plane->helper_private; funcs->atomic_async_update(plane, plane_state); @@ -1667,11 +1663,17 @@ void drm_atomic_helper_async_commit(struct drm_device *dev, * plane->state in-place, make sure at least common * properties have been properly updated. */ - WARN_ON_ONCE(plane->state->fb != plane_state->fb); + WARN_ON_ONCE(plane->state->fb != new_fb); WARN_ON_ONCE(plane->state->crtc_x != plane_state->crtc_x); WARN_ON_ONCE(plane->state->crtc_y != plane_state->crtc_y); WARN_ON_ONCE(plane->state->src_x != plane_state->src_x); WARN_ON_ONCE(plane->state->src_y != plane_state->src_y); + + /* + * Make sure the FBs have been swapped so that cleanups in the + * new_state performs a cleanup in the old FB. + */ + WARN_ON_ONCE(plane_state->fb != old_fb); } } EXPORT_SYMBOL(drm_atomic_helper_async_commit); diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h index f9c94c2a1364..f7bbd0b0ecd1 100644 --- a/include/drm/drm_modeset_helper_vtables.h +++ b/include/drm/drm_modeset_helper_vtables.h @@ -1185,6 +1185,14 @@ struct drm_plane_helper_funcs { * current one with the new plane configurations in the new * plane_state. * + * Drivers should also swap the framebuffers between current plane + * state (&drm_plane.state) and new_state. + * This is required since cleanup for async commits is performed on + * the new state, rather than old state like for traditional commits. + * Since we want to give up the reference on the current (old) fb + * instead of our brand new one, swap them in the driver during the + * async commit. + * * FIXME: * - It only works for single plane updates * - Async Pageflips are not supported yet