Before re-using a VkCommandBuffer, we need to wait for its
operations to complete. Right now we unconditionally wait for
rendering to complete in vulkan_end(), however we have plans to
fix this [1]. To fully avoid blocking, we need to handle multiple
command buffers in flight at the same time (e.g. for multi-output,
or for rendering followed by texture uploads).
Implement a pool of command buffers. When we need to render, we
pick a command buffer from the pool which has completed its
operations. If we don't find one, try to allocate a new command
buffer. If we don't have slots in the pool anymore, block like we
did before.
[1]: https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/3574
Up until now we were using a VkFence for GPU-to-CPU
synchronization. This has some limitations that become a blocker
when trying to have multiple command buffers in flight at once
(e.g. for multi-output). It's desirable to implement a command
buffer pool [1], but VkFence cannot be used to track command buffer
completion for individual subpasses.
Let's just switch to timeline semaphores [2], which fix this issue,
make synchronization a lot more ergonomic and are a core Vulkan 1.2
feature.
[1]: https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/3802
[2]: https://www.khronos.org/blog/vulkan-timeline-semaphores
Added wlr_vk_renderer_get_* functions to allow get the VkInstance,
VkPhysicalDevice, VkDevice, queue family of a wlr_vk_renderer.
Added wlr_vk_renderer_get_current_image_attribs function to allow get
the VkImage of current renderer buffer to use on compositors.
Added wlr_renderer_is_vk function, it's like the wlr_renderer_is_gles2,
returns true if the wlr_renderer is a wlr_vk_renderer.
Added wlr_vk_image_get_attribs function to get a VkImage and it's
extras information (e.g. a VkImageLayout and VkImageFormat of the
VkImage) from a wlr_texture.
In wlroots we add comments near struct wl_list members to indicate
which type it's linked to. The Vulkan renderer had some comments
with mistakes, and some members without a comment.
We were crashing in the error codepath [1] when
wlr_drm_create_lease() fails.
To fix this, delay the creation of the wlr_drm_lease_v1 until the
request is granted. Previously we were allocating that struct early
without populating the drm_lease field. However that means we ended
up with a half-constructed struct in the error codepath which is
annoying to handle.
[1]: https://github.com/swaywm/sway/issues/7204#issuecomment-1269797356
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.
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
Instead of using low-level wl_shm_buffer and wlr_dmabuf_v1_buffer
APIs, use the unified wlr_buffer APIs. That way it doesn't matter
what the exact wlr_buffer implementation is used, any which provides
the necessary capabilities (data_ptr or dmabuf) would work.
Simplifies the logic a bit, and will make the transition to wlr_shm
easier.
