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.
`modifiers` and `external_only` are never initialized, and free'd later. This
commit explicitly initializes them to NULL to prevent segfaults on `free()`
It's not safe to destroy any resources which might still be in-use
by the GPU. Wait for any asynchronous tasks to complete before
destroying everything.
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
If NULL is returned by vkGetDeviceProcAddr(), either the driver
is buggy, either the wlroots code is buggy. For a valid device and
command name, drivers are not allowed to return NULL per the spec.
This mirrors what the GLES2 renderer does in load_gl_proc().
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()")
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.
Instead of filling the fields one by one, use a struct initializer.
This avoids repeating the name of the variable and is more
consistent with the wlroots code style.
find_extensions() is clunky to use when checking only a single
extension, and it's surprising that it returns NULL on success.
Simplify by replacing it with a check_extension() function which
just checks whether a single extension is in the list.
