Enable scene-tree direct scanout of a single buffer with various options
for scaling and source crop. This is intended to support direct scanout
for fullscreen video with/without scaling, letterboxing/pillarboxing
(e.g. 4:3 content on a 16:9 display), and source crop (e.g. when
1920x1088 planes are used for 1920x1080 video).
This works by explicitly specifying the source crop and destination box
for the primary buffer in the output state. DRM atomic and libliftoff
backends will turn this into a crop and scale of the plane (assuming the
hardware supports that). For the Wayland/X11/DRM-legacy backends I just
reject this so scanout will be disabled.
The previous behaviour is preserved if buffer_src_box and buffer_dst_box
are unset: the buffer is displayed at native size at the top-left of the
output with no crop.
The change to `struct wlr_output_state` makes this a binary breaking
change (but this works transparently for scene-tree compositors like
labwc after a recompile).
When a compositors submits a wlr_output_state with
WLR_OUTPUT_STATE_ADAPTIVE_SYNC_ENABLED set and
adaptive_sync_enabled = false on an output which doesn't support
adaptive sync, we'd fail the commit. Fix this.
This bug was previously hidden because wlr_output_commit() drops
no-op changes from wlr_output_state.committed.
This centralizes logic common for both the atomic and libliftoff
backends. Additionally, a struct will make it easier to implement
multi-connector commits (since it can be stored in an array).
Use the same logic for cursor FBs as we currently use for primary
FBs. This also fixes the same bug as [1] but in a different, more
robust way.
The new logic integrates better with atomic and will be required
anyways in the future when set_cursor will be superseded by a better
API.
[1]: https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/4577
Introduce a per-page-flip tracking struct passed to the kernel
when we request a page-flip event for an atomic commit. The kernel
will pass us back this pointer when delivering the event.
This eliminates any risk of mixing up events together. In particular,
if two events are pending, or if the CRTC of a connector is swapped,
we no longer blow up in the page-flip event handler.
Closes: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3753
Instead of having a pending_fb field on the struct wlr_drm_plane,
move it to struct wlr_drm_connector_state. That way, there's no
risk having a stale pending FB around: the state doesn't survive
across tests and commits.
The cursor is a special case because it's disconnected from the
atomic state: the wlr_backend_impl.set_cursor hook sets the cursor
for the next commit. Move the field to
wlr_drm_connector.cursor_pending_fb.
We'll move the pending primary FB into the connector state in the
next commit, dropping wlr_drm_plane.pending_fb in the process.
Introduce a dedicated field for the cursor, which has to be managed
in a special way due to our set_cursor API.
Previously, adaptive sync was just a hint and wouldn't make any
atomic commit fail if the backend didn't support it. The main reason
is wlr_output_test wasn't supported at the time.
Now that we have a way for compositors to test whether a change can
work, let's remove the exception for adaptive sync and convert it to
a regular output state field.
The BO handle table exists to avoid double-closing a BO handle,
which aren't reference-counted by the kernel. But if we can
guarantee that there is only ever a single ref for each BO handle,
then we don't need the BO handle table anymore.
This is possible if we create the handle right before the ADDFB2
IOCTL, and close the handle right after. The handles are very
short-lived and we don't need to track their lifetime.
Because of multi-planar FBs, we need to be a bit careful: some
FB planes might share the same handle. But with a small check, it's
easy to avoid double-closing the same handle (which wouldn't be a
big deal anyways).
There's one gotcha though: drmModeSetCursor2 takes a BO handle as
input. Saving the handles until drmModeSetCursor2 time would require
us to track BO handle lifetimes, so we wouldn't be able to get rid
of the BO handle table. As a workaround, use drmModeGetFB to turn the
FB ID back to a BO handle, call drmModeSetCursor2 and then immediately
close the BO handle. The overhead should be minimal since these IOCTLs
are pretty cheap.
Closes: https://github.com/swaywm/wlroots/issues/3164
Previously, we were copying wlr_output_state on the stack and
patching it up to be guaranteed to have a proper drmModeModeInfo
stored in it (and not a custom mode). Also, we had a bunch of
helpers deriving DRM-specific information from the generic
wlr_output_state.
Copying the wlr_output_state worked fine so far, but with output
layers we'll be getting a wl_list in there. An empty wl_list stores
two pointers to itself, copying it on the stack blindly results in
infinite loops in wl_list_for_each.
To fix this, rework our DRM backend to stop copying wlr_output_state,
instead add a new struct wlr_drm_connector_state which holds both
the wlr_output_state and additional DRM-specific information.
Using GBM to import DRM dumb buffers tends to not work well. By
using GBM we're calling some driver-specific functions in Mesa.
These functions check whether Mesa can work with the buffer.
Sometimes Mesa has requirements which differ from DRM dumb buffers
and the GBM import will fail (e.g. on amdgpu).
Instead, drop GBM and use drmPrimeFDToHandle directly. But there's
a twist: BO handles are not ref'counted by the kernel and need to
be ref'counted in user-space [1]. libdrm usually performs this
bookkeeping and is used under-the-hood by Mesa.
We can't re-use libdrm for this task without using driver-specific
APIs. So let's just re-implement the ref'counting logic in wlroots.
The wlroots implementation is inspired from amdgpu's in libdrm [2].
Closes: https://github.com/swaywm/wlroots/issues/2916
[1]: https://gitlab.freedesktop.org/mesa/drm/-/merge_requests/110
[2]: 1a4c0ec9ae/amdgpu/handle_table.c
Historically we haven't allowed direct scan-out for legacy KMS,
because legacy misses the functionality to make sure a buffer can
be scanned out. However with renderer v6 the backend can't figure
out anymore whether the buffer comes from its internal swap-chain,
because the backend doesn't have an internal swap-chain.
The legacy KMS API guarantees that the driver won't reject a buffer
as long as it's been allocated with the same parameters as the
previous one. Let's check this in legacy_crtc_test.
Right now callers of drm_crtc_commit need to check whether the
interface is legacy or atomic before passing the TEST_ONLY flag.
Additionally, the fallbacks for legacy are in-place in the common
code.
Add a test_only arg to the crtc_commit hook. This way, there's no
risk to pass atomic-only flags to the legacy function (add an assert
to ensure this) and all of the legacy-specific logic can be put back
into legacy.c (done in next commit).
Replace it with a new drm_connector_state_is_modeset function that
decides whether a modeset is necessary directly from the
wlr_output_state which is going to be applied.
Stop assuming that the state to be applied is in output->pending in
crtc_commit. This will allow us to remove ephemeral fields in
wlr_drm_crtc, which are used scratch fields to stash temporary
per-commit data.
Stop using wlr_drm_surface.{width,height} to figure out the size of a
gbm_bo. In the future we'll stop using wlr_drm_plane.surf, so these will
be zero. Instead, rely on gbm_bo_get_{width,height}.
Simplify and unify connector-specific logging with a new
wlr_drm_conn_log macro. This makes it easier to understand which
connector a failure is about, without having to explicitly integrate the
connector name in each log message.
Previously, we only had the pending state (crtc->pending, crtc->mode and
crtc->active). This causes issues when a commit fails: the pending state
is left as-is, and the next commit may read stale data from it.
This will also cause issues when implementing test-only commits: we need
to rollback the pending CRTC state after a test-only commit.
Introduce separate pending and current CRTC states. Properly update the
current state after a commit.
GAMMA_LUT_SIZE isn't an atomic property. It can be used with the legacy
interface too. So we can unify both codepaths and remove
wlr_drm_interface.crtc_get_gamma_size.
It's no guaranteed to exist though, so we still need to keep the
fallback.
This requires functions without a prototype definition to be static.
This allows to detect dead code, export less symbols and put shared
functions in headers.
