Since 1d581656c7 ("backend/drm: set "max bpc" to the max") we
set the "max bpc" property to the maximum value. The kernel driver
is supposed to clamp this value depending on hardware capabilities.
All kernel drivers lower the value depending on the GPU capabilities.
However, none of the drivers lower the value depending on the DP-MST
link capabilities. Thus, enabling a 4k@60Hz mode can fail on some
DP-MST setups due to the "max bpc" property.
Additionally, it's not a good idea to unconditionally set "max bpc"
to the max. A high bpc consumes more lanes and more clock speed,
which means higher power consumption and the busy lanes cannot be
used for something else (e.g. other data transfers on a USB-C cable).
For now, let's tie the "max bpc" to the pixel format of the buffer.
Introduce a heuristic to make "high bit-depth buffer" a synonym of
"I want the best quality".
This is not perfect: a "max bpc" higher than 8 might be desirable
for pixel formats with a color depth of 8 bits, for instance when
the color management KMS properties are used. But we don't really
support that yet, so let's leave this for later.
Closes: https://github.com/swaywm/sway/issues/7367
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.
"max bpc" is a maximum value, the driver is free to choose a
smaller value depending on the bandwidth available.
Some faulty monitors misbehave with higher bpc values. We'll add
a workaround if users get hit by these in practice.
References: https://gitlab.freedesktop.org/wayland/weston/-/issues/612
CTA-861-G says that "graphics" is used to indicate non-analog (ie,
digital) content. With that bit set, the sink should turn off analog
reconstruction and other related filtering.
The wlr_output API requires compositors to wait for wlr_output.frame
before submitting a new buffer. However, compositors can perform a
commit which doesn't involve a buffer anytime.
If the commit is a modeset, we set DRM_MODE_ATOMIC_ALLOW_MODESET and
block until the commit is done. If it isn't, we currently always
perform a non-blocking commit. This is an issue because a previous
page-flip might still be in flight kernel-side, returning EBUSY.
Fix this by using blocking commits when a buffer isn't submitted by
the compositor.
Closes: https://github.com/swaywm/sway/issues/6962
References: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/2239
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
This allows the kernel to access our buffer damage. Some drivers
can take advantage of this, e.g. for PSR2 panels (Panel Self
Refresh) or for transfer over USB.
Closes: https://github.com/swaywm/wlroots/issues/1267
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}.
The DRM backend is a little special when it comes to wlr_outputs: the
wlr_drm_connectors are long-lived and are created even when no screen is
connected.
A wlr_drm_connector only advertises a wlr_output to the compositor when
a screen is connected. As such, most of wlr_output's state is invalid
when the connector is disconnected.
We want to stop using wlr_output state on disconnected connectors.
Introduce wlr_drm_connector.name which is always valid regardless of the
connector status to avoid reading wlr_output.name when disconnected.
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.
If the atomic commit fails or is test-only, rollback
wlr_drm_crtc.{mode_id,gamma_lut} blob IDs to their previous value. This
prevents the next commits from failing or applying test-only state.
We already have the logic to fallback to the legacy interface above. We
just need to avoid calling atomic_add with a zero prop ID.
Closes: https://github.com/swaywm/wlroots/issues/2187
We don't need a per-CRTC atomic request anymore. Let's make the request
per-commit so that it's easier to debug.
This is also groundwork for supporting wlr_output_test properly.
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 is a type which manages gbm_surfaces and imported dmabufs in the
same place, and makes the lifetime management between the two shared. It
should lead to easier to understand code, and fewer special cases.
This also contains a fair bit of refactoring to start using this new
type.
Co-authored-by: Simon Ser <contact@emersion.fr>
Simon Ser
vanfanel
Scott Anderson