We were calling drm_connector_supports_vrr() before
drm_connector_alloc_crtc(). Thus, when an output is currently off,
the VRR test would always fail, because it checks that the
vrr_enabled CRTC prop exists.
The following situation can be dangerous:
- Output DP-1 is plugged in, compositor enables it.
- User VT switches away.
- User unplugs DP-1.
- User VT switches back.
- scan_drm_connectors() figures out the output is now disconnected,
uninitializes the struct wlr_output.
- The loop restoring previous output state in handle_session_active()
accesses the struct wlr_output to figure out what to restore.
By chance, we zero out the struct wlr_output after uninitializing it,
so enabled and current_mode will always be zero. But let's make sure
we handle this case explicitly, to remind future readers that it exists
and make the code less fragile.
The old drm_connector_set_mode() function did that by calling
drm_crtc_page_flip(). We lost this in the refactoring.
Fixes: f216e97983 ("backend/drm: drop drm_connector_set_mode()")
Once we are DRM master, the CRTC cannot be changed behind our back
except during a VT switch.
After a VT switch, we try to restore whatever KMS state we had last
programmed. Reloading the current CRTC from KMS breaks this and
can result in a modeset without a FB.
Closes: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3432
The drm_connector_commit_state() call in handle_session_active()
was not resulting in any atomic commit, because it didn't match any
of the if branches: active = true, no new buffer was committed,
and adaptive sync/gamma LUT were unchanged. Thus the commit was a
no-op.
Later on, when the compositor performs regular page-flips, the
kernel would return EINVAL indicating that a modeset was needed.
Rework the logic to use a non-blocking page-flip commit if a buffer
was committed, and use a blocking commit if the connector is on or
is being disabled. The only case where we should skip the atomic
commit is when disabling (active = false) an already-disabled
connector (conn->crtc == NULL).
Note, 6936e163b5 ("backend/drm: short-circuit no-op commits")
has introduced early returns for other situations where we don't
need to perform an atomic commit (e.g. updating scale or transform
of an output).
Fixes: f216e97983 ("backend/drm: drop drm_connector_set_mode()")
Closes: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3432
Extract the logic to fetch the current mode to a separate function
to make it more readable. Stop dying in an assert when
get_drm_prop_blob() fails. Always make it so the drmModeModeInfo
pointer is allocated so that we can free() it unconditionally.
We already have disconnect_drm_connector() to handle the
CONNECTED → DISCONNECTED transition. Let's add
connect_drm_connector() to handle DISCONNECTED → CONNECTED. This
makes scan_drm_connectors() shorter and easier to follow.
No functional change, literally just moving code around.
We were using the legacy API (with a detour through drmModeEncoder)
to find out the current CRTC for a connector. Use the atomic API
when available.
Also extract the whole logic into a separate function for better
readability, and better handle errors.
Instead of special-casing modesets, we can just cut the wrapper
and directly call drm_crtc_page_flip(). drm_connector_test() should
already have the checks previously done in drm_connector_set_mode(),
all we need to do is update enabled/mode after a successful atomic
commit.
This field becomes stale too easily: for instance, see 6adca4089c
("backend/drm: don't unconditionally set desired_enabled").
Additionally, drm_connector_alloc_crtc() needs to do some weird
dance, restoring its previous value.
Instead, add a connector arg to realloc_crtcs() to indicate a new
connector we want to enable.
We were unconditonally setting desired_enabled = true for all
connected connectors. This makes realloc_crtcs() always keep a CRTC
active for these, even if the user doesn't want to enable them.
When starting up, the compositor might call wlr_output_set_mode()
with a mode which is already the current one. wlroots will detect
this and make the wlr_output_set_mode() call a no-op. During the
next wlr_output_commit() call, wlroots will perform an atomic
commit without the ALLOW_MODESET flag.
This is an issue, because some drivers need ALLOW_MODESET even if
the mode is the same. For instance, if the FB stride or modifier
changed, some drivers require a modeset.
Add a new flag "allow_artifacts" which is set when the compositor
calls mode-setting functions. Use this flag to figure out whether
we want to perform atomic commits with ALLOW_MODESET.
(The name "allow_artifacts" is picked because ALLOW_MODESET is a
misnomer, see [1].)
[1]: https://patchwork.freedesktop.org/patch/505107/
Closes: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3499
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
The EDID 1.4 spec says that the serial number is optional:
> If this field is not used, then enter “00h, 00h, 00h, 00h”.
Leave the wlr_output.serial field NULL in that case, and hide it
from the output description.
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.
Some output commits (changing e.g. the output scale or transform)
don't require any change in the KMS state. Instead of going through
a KMS commit, return early. Blocking KMS commits can be expensive.
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
This allows the make/model/serial to be NULL when unset, and allows
them to be longer than the hardcoded array length.
This is a breaking change: compositors need to handle the new NULL
case, and we stop setting make/model to useless "headless" or
"wayland" strings.
Prior to [1], if an entry in a DRM format set was different than a
single LINEAR modifier, implicit modifiers were always allowed. This
has changed and now implicit modifiers are only allowed if INVALID
is in the list of modifiers.
So now we can safely enable explicit modifiers for cross-GPU imports,
without risking receiving buffers with an implicit modifier. This
should improve perf a bit on setups where two GPUs from the same vendor
are used.
This fixes the first bullet point from [2].
[1]: https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/3231
[2]: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3331
Maintaining our internal table up-to-date is tedious: one needs to
manually go through the PnP ID registry [1] and check whether we're
missing any entry.
udev_hwdb already has an API to fetch a manufacturer name from its
PnP ID. Use that instead.
[1]: https://uefi.org/pnp_id_list
wlroots picks names for all outputs, but it might be desirable for
compositor to override it.
For instance, Sway will use a headless output as a fallback in
case no outputs are connected. Sway wants to clearly label the
fallback output as such and label "real" headless outputs starting
from HEADLESS-1.
drmModeAddFB2 doesn't support explicit modifiers. Only accept INVALID
which indicates an implicit modifier and LINEAR which may indicate
that GBM_BO_USE_LINEAR has been used.
They are never used in practice, which makes all of our flag
handling effectively dead code. Also, APIs such as KMS don't
provide a good way to deal with the flags. Let's just fail the
DMA-BUF import when clients provide flags.
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
drmModeAddFB2 doesn't support explicit modifiers. Only accept INVALID
which indicates an implicit modifier and LINEAR which may indicate
that GBM_BO_USE_LINEAR has been used.
Instead of ensuring the renderer and allocator are initialized in each
backend, do it in wlr_backend_autocreate. This allows compositors to
create backends without any renderer/allocator if they side-step
wlr_backend_autocreate.
Since the wlr_backend_get_renderer and backend_get_allocator end up
calling wlr_renderer_autocreate and wlr_allocator_autocreate, it sounds
like a good idea to centralize all of the opimionated bits in one place.
Expose the panel orientation with wlr_drm_connector_get_panel_orientation.
Leave it to the compositor to consume this information and configure the
output accordingly.
Closes: https://github.com/swaywm/wlroots/issues/1581
Modesets require a buffer. The DRM backend tried to auto-enable
outputs when a CRTC becomes available in the past, but now that
fails because no buffer is available.
Instead of having this magic inside the DRM backend, a better
approach is to do it in the compositor or in an optional helper.
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
The Coordinated Video Timings (CVT) spec [1] defines two types of
timings: the "CVT standard CRT" timings and the "CVT reduced blanking"
timings (see section 3.6).
The standard CRT timings include pauses in the video stream to allow
CRT displays to reposition their electron beam at the end of each
horizontal scan line [2]. While this was desirable a few decades ago,
nowadays we can just generate a CVT reduced blanking timing by default.
wlroots users can still set full custom DRM modes via
wlr_drm_connector_add_mode.
[1]: https://glenwing.github.io/docs/VESA-CVT-1.2.pdf
[2]: https://en.wikipedia.org/wiki/Coordinated_Video_Timings#Reduced_blanking
Simon Ser
illiliti
Alexander Orzechowski
Simon Zeni
vanfanel
Isaac Freund
vaxerski
Samuel Čavoj
Chris Chamberlain
Haelwenn (lanodan) Monnier
Kirill Primak
Elyes HAOUAS