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From:   Javier Martinez Canillas <javierm@redhat.com>
To:     linux-kernel@vger.kernel.org
Cc:     Thomas Zimmermann <tzimmermann@suse.de>,
        Maxime Ripard <mripard@kernel.org>,
        Pekka Paalanen <pekka.paalanen@collabora.com>,
        Sima Vetter <daniel.vetter@ffwll.ch>,
        Erico Nunes <nunes.erico@gmail.com>,
        Simon Ser <contact@emersion.fr>,
        Bilal Elmoussaoui <belmouss@redhat.com>,
        Javier Martinez Canillas <javierm@redhat.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        David Airlie <airlied@gmail.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        dri-devel@lists.freedesktop.org, linux-doc@vger.kernel.org
Subject: [PATCH v3 5/5] drm/todo: Add entry about implementing buffer age for damage tracking
Date:   Sun, 19 Nov 2023 11:57:01 +0100
Message-ID: <20231119105709.3143489-6-javierm@redhat.com>
In-Reply-To: <20231119105709.3143489-1-javierm@redhat.com>
References: <20231119105709.3143489-1-javierm@redhat.com>
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Currently, only damage tracking for frame damage is supported. If a driver
needs to do buffer damage (e.g: the framebuffer attached to plane's state
has changed since the last page-flip), the damage helpers just fallback to
a full plane update.

Add en entry in the TODO about implementing buffer age or any other damage
accumulation algorithm for buffer damage handling.

Suggested-by: Simon Ser <contact@emersion.fr>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
---

(no changes since v1)

 Documentation/gpu/todo.rst | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index b62c7fa0c2bc..5c43a958814b 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -782,6 +782,26 @@ Contact: Hans de Goede
 
 Level: Advanced
 
+Buffer age or other damage accumulation algorithm for buffer damage handling
+============================================================================
+
+Drivers that do per-buffer uploads, need a buffer damage handling (rather than
+frame damage like drivers that do per-plane or per-CRTC uploads), but there is
+no support to get the buffer age or any other damage accumulation algorithm.
+
+For this reason, the damage helpers just fallback to a full plane update if the
+framebuffer attached to a plane has changed since the last page-flip.
+
+This should be improved to get damage tracking properly working on drivers that
+do per-buffer uploads.
+
+More information about damage tracking and references to learning materials in
+`Damage Tracking Properties <https://docs.kernel.org/gpu/drm-kms.html#damage-tracking-properties>`_
+
+Contact: Javier Martinez Canillas <javierm@redhat.com>
+
+Level: Advanced
+
 Outside DRM
 ===========
 
-- 
2.41.0