c7a4722971
Introduce a new DRM_IOCTL_SYNCOBJ_EVENTFD IOCTL which signals an eventfd from a syncobj. This is useful for Wayland compositors to handle wait-before-submit. Wayland clients can send a timeline point to the compositor before the point has materialized yet, then compositors can wait for the point to materialize via this new IOCTL. The existing DRM_IOCTL_SYNCOBJ_TIMELINE_WAIT IOCTL is not suitable because it blocks. Compositors want to integrate the wait with their poll(2)-based event loop. Requirements for new uAPI: - User-space patch: https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/4262 - IGT: https://lists.freedesktop.org/archives/igt-dev/2023-July/057893.html v2: - Wait for fence when flags is zero - Improve documentation (Pekka) - Rename IOCTL (Christian) - Fix typo in drm_syncobj_add_eventfd() (Christian) v3: - Link user-space + IGT patches - Add reference from overview docs v4: fix IOCTL number conflict with GETFB2 (Nicholas Choi, Vitaly Prosyak) Signed-off-by: Simon Ser <contact@emersion.fr> Reviewed-by: Christian König <christian.koenig@amd.com> Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com> Cc: Jason Ekstrand <jason@jlekstrand.net> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl> Cc: Daniel Stone <daniel@fooishbar.org> Cc: James Jones <jajones@nvidia.com> Cc: Austin Shafer <ashafer@nvidia.com> Cc: Vitaly Prosyak <vprosyak@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20230714111257.11940-1-contact@emersion.fr
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.