From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794326607; b=OoW7yzN1hMm+Vf/jGCcFXBPFcyNrLIPsl79YLtBiei3hAdCzifw5xFOHpa9qQx2SjHlK ZI+yAv8AaxdrKysDc5MWz9vpKGoTciaMTFXgATx4vwLlPhcJ2oxOjT1M5dN9OYlfqdQRx iRZ3KOcE8kuTpcvzy3Oy23Cy4LEmo4z0LEf+5rGQtljjElYirW89B5puyhFsvytcW1KcO GyC75Z4icTfvKnnhFHSOaxN7ltz2mgRCvSp1dfhrKRRI2VFWXpqesu+R16aWqsMqCvp18 u6YA4Xh1LzbE2HdNbxzJ/9IAEr5fyXfm2AK4VsdpiwP423ytxbKlMtNJqEZxk9y4QWQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794326607; h=Received:DKIM-Signature:From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:References:In-Reply-To:To:Cc: X-Mailer:X-Developer-Signature:X-Developer-Key; bh=wG0Eagp7MG3/cX4z23ZRTmSZPVnCef9+gN4tgfJWSOQ=; b=RLKz2uGeiMrPFmVD9Eh7WB53YEWJlydK8+H67I/SEUrQAmqblOhmQ+lqD3M4LIO4uEmr giTHSOzkFYMAC+wBFnm1bcmYRpLzbPslBY9jOphu2/BMSXXAUTY1CuBbRuuDtNAk2ZcoX bwgonc8RcMvxEHDwkuseb3zRQ5V0jnyi/l9OOrH6ecak6707ND5fdGJmHpt1F2x13kM74 DqmFVzxRMaqvMkX2pvJPNUGGENuTs3cMoXp/frYLHSTmgXLU3PaRua9g34ddIWvZaRwrR EONQsAu5qjSyB9GcahChPu6MPRO1WQSQC6Hs1RgHhBvAOCIMcwlTWCc10SAddwAmUdQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=JLAwxsKP; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 35FB560A3827 for ; Tue, 10 Nov 2026 16:03:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=JLAwxsKP Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B9961F008AB; Tue, 10 Nov 2026 16:03:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794326607; bh=wG0Eagp7MG3/cX4z23ZRTmSZPVnCef9+gN4tgfJWSOQ=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=JLAwxsKPcnfu/VM5zMyphtUlR0XDAZoezGcc68teJ4PqBNSsy8oWHfjtfKtJ3d3j1 TRbS3A/4FwlnJ7xLNdTktalaHeU2Rt4fdJTh16mX6ndSRl2pL14mCjYQWBzZp6YVdN K2ZZ6+1LOGqU1xWjXOky5v8m+HylPusWcSnBaqZmFxwf24zKFdwhdyTK+4AFDvRrk6 a5OW+5hiWatpUOFdM3Be0ClOAnVtUi59mQi+1x/KTXeTZ4ZhYqXtPoKWmkhbLRETPe eOmTdOXJfyDr5Mepay5hevEyV6W/1AcXGKwepq7OFjBEXXdsNSmbOekaOCQMLmTUC/ GwAFUkeVzlJ+g== From: Maxime Ripard Date: Tue, 10 Nov 2026 17:02:56 +0100 Subject: [PATCH v9 09/10] drm/atomic-uapi: Add DRM_MODE_ATOMIC_RESET flag X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261110-drm-reset-state-flag-v9-9-ddb0e26324a0@kernel.org> References: <20261110-drm-reset-state-flag-v9-0-ddb0e26324a0@kernel.org> In-Reply-To: <20261110-drm-reset-state-flag-v9-0-ddb0e26324a0@kernel.org> To: Maarten Lankhorst , Thomas Zimmermann , David Airlie , Simona Vetter , Louis Chauvet , Haneen Mohammed , Melissa Wen Cc: Daniel Stone , Harry Wentland , Jocelyn Falempe , =?utf-8?q?Jonas_=C3=85dahl?= , =?utf-8?q?Michel_D=C3=A4nzer?= , Pekka Paalanen , Sebastian Wick , Simon Ser , Victoria Brekenfeld , Xaver Hugl , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Maxime Ripard X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=9577; i=mripard@kernel.org; h=from:subject:message-id; bh=Kq13t0MXJreVvHAZBnZ/EJVaEivPSaiF+0ujw2efV1Q=; b=owGbwMvMwCmsHn9OcpHtvjLG02pJDFmfHfQd9xl+O7jn3/20/bzstu1zdyzU3hjzpfjh5WRJ5 6sK90xZO6ayMAhzMsiKKbI8kQk7vbx9cZWD/cofMHNYmUCGMHBxCsBEuHwZa3i+vmaQiv460Sza dZce20JxrdhtUUv3qomemLK4t5nFqrjdVWkiM8t8XSXjAla28HuzGBsWdbw7u+HeNWv939H1V+4 dr+4Q08vcckyUU9Npg6nvI26vXXEHg16U+b73iJx3jalcWxgA X-Developer-Key: i=mripard@kernel.org; a=openpgp; fpr=BE5675C37E818C8B5764241C254BCFC56BF6CE8D From: Sebastian Wick Userspace currently has no atomic way to reset all KMS object states to their defaults. To bring a display pipeline to a known state, a compositor must explicitly set every property on every object, which requires tracking which properties exist and what their defaults are. Introduce DRM_MODE_ATOMIC_RESET (0x0800) which, when passed to the atomic ioctl, fills the commit with default states for all KMS objects before applying the properties supplied in the request. Properties not explicitly included in the commit remain at their defaults (CRTCs inactive, planes disabled, connectors unbound, and so on). The flag cannot be combined with DRM_MODE_PAGE_FLIP_ASYNC, since a full state reset is incompatible with an async flip. Since the commit contains every CRTC of the device or lease, including the ones that are disabled before and after it, no page flip event is attached to those: they can't report a flip, and drm_atomic_crtc_check() would reject the whole commit. Such a CRTC doesn't count towards the CRTCs that can signal either, so a commit that leaves them all disabled while asking for an event is still rejected instead of waiting for an event that would never come. Signed-off-by: Sebastian Wick Co-developed-by: Maxime Ripard Signed-off-by: Maxime Ripard --- drivers/gpu/drm/drm_atomic.c | 3 +++ drivers/gpu/drm/drm_atomic_uapi.c | 56 ++++++++++++++++++++++++++++++++++++--- drivers/gpu/drm/drm_ioctl.c | 5 ++++ include/uapi/drm/drm.h | 10 +++++++ include/uapi/drm/drm_mode.h | 17 +++++++++++- 5 files changed, 87 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c index b469a8169ca6..35d2e5603cb2 100644 --- a/drivers/gpu/drm/drm_atomic.c +++ b/drivers/gpu/drm/drm_atomic.c @@ -1611,10 +1611,13 @@ EXPORT_SYMBOL(drm_atomic_get_new_bridge_state); * the current state. * * Color operations are not checked because they always use * drm_atomic_helper_colorop_create_state() and do not have a per-driver hook. * + * This is used to report the %DRM_CAP_ATOMIC_RESET capability to userspace, + * and as a precondition in drm_atomic_commit_fill_with_defaults(). + * * Returns: * True if all objects implement atomic_create_state, false otherwise. */ bool drm_atomic_implements_create_state(struct drm_device *dev) { diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c index 1eebcf6f5e05..1a89175318d0 100644 --- a/drivers/gpu/drm/drm_atomic_uapi.c +++ b/drivers/gpu/drm/drm_atomic_uapi.c @@ -1438,24 +1438,55 @@ static int prepare_signaling(struct drm_device *dev, if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY) return 0; for_each_new_crtc_in_state(state, crtc, crtc_state, i) { s32 __user *fence_ptr; + bool page_flip_event; fence_ptr = get_out_fence_for_crtc(crtc_state->state, crtc); - if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT || fence_ptr) { + page_flip_event = arg->flags & DRM_MODE_PAGE_FLIP_EVENT; + + /* + * A commit with the DRM_MODE_ATOMIC_RESET flag contains + * every CRTC of the device or lease, even the ones that are + * disabled before and after the commit. Those can't report + * a page flip, and drm_atomic_crtc_check() would reject the + * whole commit, so don't attach any event to them. + */ + if (page_flip_event && !fence_ptr && + (arg->flags & DRM_MODE_ATOMIC_RESET) && + !crtc_state->active) { + struct drm_crtc_state *old_crtc_state; + + old_crtc_state = drm_atomic_get_old_crtc_state(state, crtc); + page_flip_event = old_crtc_state->active; + } + + /* + * A lessee commit with the DRM_MODE_ATOMIC_RESET flag also + * contains unleased CRTCs, pulled in because a leased plane + * or connector is bound to them. Those CRTCs belong to + * another master, so the lessee can't get a page flip from + * them: don't attach any event to them, and don't count + * them towards the CRTCs that can report one. + */ + if (page_flip_event && (arg->flags & DRM_MODE_ATOMIC_RESET) && + !drm_lease_held(file_priv, crtc->base.id)) + page_flip_event = false; + + if (page_flip_event || fence_ptr) { struct drm_pending_vblank_event *e; e = create_vblank_event(crtc, arg->user_data); if (!e) return -ENOMEM; crtc_state->event = e; } - if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) { + if (page_flip_event) { struct drm_pending_vblank_event *e = crtc_state->event; ret = drm_event_reserve_init(dev, file_priv, &e->base, &e->event.base); if (ret) { @@ -1492,11 +1523,12 @@ static int prepare_signaling(struct drm_device *dev, } crtc_state->event->base.fence = fence; } - c++; + if (page_flip_event) + c++; } for_each_new_connector_in_state(state, conn, conn_state, i) { struct drm_writeback_connector *wb_conn; struct drm_out_fence_state *f; @@ -1671,10 +1703,17 @@ int drm_mode_atomic_ioctl(struct drm_device *dev, drm_dbg_atomic(dev, "commit failed: page-flip event requested with test-only commit\n"); return -EINVAL; } + if ((arg->flags & DRM_MODE_ATOMIC_RESET) && + (arg->flags & DRM_MODE_PAGE_FLIP_ASYNC)) { + drm_dbg_atomic(dev, + "commit failed: reset cannot be combined with async flip\n"); + return -EINVAL; + } + state = drm_atomic_commit_alloc(dev); if (!state) return -ENOMEM; drm_modeset_acquire_init(&ctx, DRM_MODESET_ACQUIRE_INTERRUPTIBLE); @@ -1686,10 +1725,21 @@ int drm_mode_atomic_ioctl(struct drm_device *dev, copied_objs = 0; copied_props = 0; fence_state = NULL; num_fences = 0; + if (arg->flags & DRM_MODE_ATOMIC_RESET) { + if (!drm_atomic_implements_create_state(dev)) { + ret = -EOPNOTSUPP; + goto out; + } + + ret = drm_atomic_commit_fill_with_defaults(file_priv, state); + if (ret) + goto out; + } + for (i = 0; i < arg->count_objs; i++) { uint32_t obj_id, count_props; struct drm_mode_object *obj; if (get_user(obj_id, objs_ptr + copied_objs)) { diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index 9039a39c4324..f666a13da6bf 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -31,10 +31,11 @@ #include #include #include #include +#include #include #include #include #include #include @@ -302,10 +303,14 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_ break; case DRM_CAP_ATOMIC_ASYNC_PAGE_FLIP: req->value = drm_core_check_feature(dev, DRIVER_ATOMIC) && dev->mode_config.async_page_flip; break; + case DRM_CAP_ATOMIC_RESET: + req->value = drm_core_check_feature(dev, DRIVER_ATOMIC) && + drm_atomic_implements_create_state(dev); + break; default: return -EINVAL; } return 0; } diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h index bc7ef7684099..b6e2f2edd122 100644 --- a/include/uapi/drm/drm.h +++ b/include/uapi/drm/drm.h @@ -793,10 +793,20 @@ struct drm_gem_change_handle { * If set to 1, the driver supports &DRM_MODE_PAGE_FLIP_ASYNC for atomic * commits. */ #define DRM_CAP_ATOMIC_ASYNC_PAGE_FLIP 0x15 +/** + * DRM_CAP_ATOMIC_RESET + * + * If set to 1, the driver supports the &DRM_MODE_ATOMIC_RESET flag in + * &DRM_IOCTL_MODE_ATOMIC commits. When supported, userspace can pass that + * flag to reset all KMS object states to their defaults before applying + * property changes. + */ +#define DRM_CAP_ATOMIC_RESET 0x16 + /* DRM_IOCTL_GET_CAP ioctl argument type */ struct drm_get_cap { __u64 capability; __u64 value; }; diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h index ed1a660a3dfd..1ab5c0fb3804 100644 --- a/include/uapi/drm/drm_mode.h +++ b/include/uapi/drm/drm_mode.h @@ -1326,10 +1326,24 @@ struct drm_mode_destroy_dumb { * To the best of the driver's knowledge, visual artifacts are guaranteed to * not appear when this flag is not set. Some sinks might display visual * artifacts outside of the driver's control. */ #define DRM_MODE_ATOMIC_ALLOW_MODESET 0x0400 +/** + * DRM_MODE_ATOMIC_RESET + * + * Reset all KMS object states (CRTCs, planes, connectors, color operations) + * to their default values before applying the properties in this commit. + * Properties not explicitly included in the commit will remain at their + * defaults (CRTCs inactive, planes disabled, connectors unbound, etc.). + * + * CRTCs that are disabled before and after the commit won't send any + * &DRM_MODE_PAGE_FLIP_EVENT. + * + * This flag cannot be combined with &DRM_MODE_PAGE_FLIP_ASYNC. + */ +#define DRM_MODE_ATOMIC_RESET 0x0800 /** * DRM_MODE_ATOMIC_FLAGS * * Bitfield of flags accepted by the &DRM_IOCTL_MODE_ATOMIC IOCTL in @@ -1338,11 +1352,12 @@ struct drm_mode_destroy_dumb { #define DRM_MODE_ATOMIC_FLAGS (\ DRM_MODE_PAGE_FLIP_EVENT |\ DRM_MODE_PAGE_FLIP_ASYNC |\ DRM_MODE_ATOMIC_TEST_ONLY |\ DRM_MODE_ATOMIC_NONBLOCK |\ - DRM_MODE_ATOMIC_ALLOW_MODESET) + DRM_MODE_ATOMIC_ALLOW_MODESET |\ + DRM_MODE_ATOMIC_RESET) struct drm_mode_atomic { __u32 flags; __u32 count_objs; __u64 objs_ptr; -- 2.56.0