From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 272ED446052 for ; Wed, 12 Aug 2026 12:57:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786539450; cv=none; b=i9Olns8Jo3VzDzSV5orDpfGUP70T8YEbq/r1mpAa4KL4LUBYcgQjgkoZDCUjmBpUmLtir82vgN4vazt2n7d94nT9qFqGPPzsRzhZ2lw/sYZ4z9i+/44x3i6EwXD7tF9u/buJm7msvCVM7yNyivY1EFVbRTz2J/g9abSc0YEtcX0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786539450; c=relaxed/simple; bh=Ub0XVyTsCEW6p5sLqcnyzHN1/fhjxjvpt306j2KiEOg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=kq5yIYcwfELSTGo3APo9TI1DbIhzTu2YcplWFYcqeOhxR5SswaXNVwpZhTxRgT8XJOakYceCb7lAW/Wz+s7MjL5/Rj3/OtgTcRFNIjX5himEOVFyLQvIyQRjZ2gQtIwoKUsWs3BqXCzYz3hR+uzO/Jdl65TMA2/eFRTC3aIhT6U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AhE8Illd; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="AhE8Illd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2C9151F00A3A; Wed, 12 Aug 2026 12:57:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786539446; bh=DnPFTOt0tndqJDX1gz+DDeONsWROJPsH75wddqa7RwE=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=AhE8IlldKPWV8wmAlP9LNl6q+UXdgkL4LfooF/o9f4COcN5NssI+cg7e1DABDIi9o jfFOWHCPJ/VVbqRuqdhcVsyk5tUx4r/dqIFB4bAIm243VMWZukErIyrP+yv78PY5kQ 4uXA4g3g8DDi7hEZZ3ZrZUeaN2TFL3mAoUOyUDKApCtopKwpLyCBAMMNEXYgoyz6NK 7m4Rmq5ucx5LbvrGNGxtBt9XrqWsTXtnw6JECh2t5cEHRRruT4Q46xr3+mNtp5G0wg mxA7JBwdpX/F5h3rCwWGrLY/jZHxPu7HKS88LttYdGZMsmLlUy4RCZ+jrdRDWKLqlS asKF29Y0IlMpw== From: Maxime Ripard Date: Wed, 12 Aug 2026 14:57:04 +0200 Subject: [PATCH RFC v2 9/9] drm/atomic-uapi: Add DRM_MODE_ATOMIC_RESET flag Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260812-drm-reset-state-flag-v2-9-e96ce13317dd@kernel.org> References: <20260812-drm-reset-state-flag-v2-0-e96ce13317dd@kernel.org> In-Reply-To: <20260812-drm-reset-state-flag-v2-0-e96ce13317dd@kernel.org> To: Maarten Lankhorst , Thomas Zimmermann , David Airlie , Simona Vetter 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=6104; i=mripard@kernel.org; h=from:subject:message-id; bh=hKVb0fz+IZAsP57og4Z9AHoGfiNKGsvTwQ0y/0S8x3o=; b=kA0DAAkTJ1/OGaI9vnYByyZiAGp8bZ6gcIOsDGJsQTwFWthw/+RfYJkX6TUphRlC3lfwHyBX1 4iVBAATCQAdFiEE5BxWy6eHo3pAP6n4J1/OGaI9vnYFAmp8bZ4ACgkQJ1/OGaI9vna+KAF/bVLg HKpEf2b6cxggrUhs1riyDkZ7qL9wcysOQJBEK34Qa/hviS1gKN4JN+Rqly5MAX9KFJbWQpBg4Sw z8QLlcWzfJCarkwz4DyA1rRRZ2JdFJOrs/0fOtYsI4loAxv+X0jk= 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. 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 | 13 +++++++++++++ drivers/gpu/drm/drm_ioctl.c | 3 +++ include/uapi/drm/drm.h | 10 ++++++++++ include/uapi/drm/drm_mode.h | 14 +++++++++++++- 5 files changed, 42 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c index d5ac10dd3148..848917bea75e 100644 --- a/drivers/gpu/drm/drm_atomic.c +++ b/drivers/gpu/drm/drm_atomic.c @@ -1621,10 +1621,13 @@ 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_can_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 1050dddadb17..cdcc6efb9a00 100644 --- a/drivers/gpu/drm/drm_atomic_uapi.c +++ b/drivers/gpu/drm/drm_atomic_uapi.c @@ -1658,10 +1658,17 @@ 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); @@ -1673,10 +1680,16 @@ 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) { + ret = drm_atomic_commit_fill_with_defaults(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 8a1ccb8932bf..31e5c42bb020 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -303,10 +303,13 @@ 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_atomic_can_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 bd435effdcee..43024028f695 100644 --- a/include/uapi/drm/drm_mode.h +++ b/include/uapi/drm/drm_mode.h @@ -1314,10 +1314,21 @@ 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.). + * + * 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 @@ -1326,11 +1337,12 @@ 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; -- 2.55.0