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use crate::Error;
use ash::vk;
use gpu_allocator::AllocationSizes;
use gpu_allocator::vulkan::{Allocator, AllocatorCreateDesc};
use std::sync::Mutex;

/// Everything that must outlive every Vulkan object the renderer hands out.
/// Fields drop in declaration order, so the allocator frees its memory before
/// the device is destroyed.
pub(crate) struct Shared {
    /// Staging buffers kept for reuse, see `Staging`.
    pub staging_pool: Mutex<Vec<crate::image::Pooled>>,
    pub allocator: Mutex<Allocator>,
    pub device: Device,
}

impl Drop for Shared {
    fn drop(&mut self) {
        let pool = std::mem::take(
            self.staging_pool
                .get_mut()
                .unwrap_or_else(|e| e.into_inner()),
        );
        let allocator = self.allocator.get_mut().unwrap_or_else(|e| e.into_inner());
        for p in pool {
            unsafe { self.device.device.destroy_buffer(p.buffer, None) };
            let _ = allocator.free(p.allocation);
        }
    }
}

/// Loaders for the extensions that dmabuf import, export and fence export
/// need. Absent when the device lacks any of them.
pub(crate) struct DmabufExt {
    pub memory_fd: ash::khr::external_memory_fd::Device,
    pub fence_fd: ash::khr::external_fence_fd::Device,
    pub modifier: ash::ext::image_drm_format_modifier::Device,
}

const DMABUF_EXTENSIONS: [&std::ffi::CStr; 5] = [
    ash::khr::external_memory_fd::NAME,
    ash::ext::external_memory_dma_buf::NAME,
    ash::ext::image_drm_format_modifier::NAME,
    ash::ext::queue_family_foreign::NAME,
    ash::khr::external_fence_fd::NAME,
];

pub(crate) struct Device {
    pub _entry: ash::Entry,
    pub instance: ash::Instance,
    pub physical: vk::PhysicalDevice,
    pub device: ash::Device,
    pub queue: Mutex<vk::Queue>,
    pub queue_family: u32,
    pub push_descriptor: ash::khr::push_descriptor::Device,
    pub dmabuf: Option<DmabufExt>,
    pub name: String,
    pub drm_node: Option<u64>,
    /// Signalled fences kept for reuse, see `FenceInner`.
    pub spare_fences: Mutex<Vec<vk::Fence>>,
}

impl Drop for Device {
    fn drop(&mut self) {
        unsafe {
            let _ = self.device.device_wait_idle();
            for f in self
                .spare_fences
                .get_mut()
                .unwrap_or_else(|e| e.into_inner())
                .drain(..)
            {
                self.device.destroy_fence(f, None);
            }
            self.device.destroy_device(None);
            self.instance.destroy_instance(None);
        }
    }
}

impl Shared {
    /// Opens the first suitable device, or the one whose name contains
    /// `MONOLITH_VK_DEVICE` when that is set. With `node`, only the device
    /// behind that DRM device number qualifies.
    pub fn new(node: Option<u64>) -> Result<Self, Error> {
        let entry = unsafe { ash::Entry::load()? };
        let app = vk::ApplicationInfo::default()
            .application_name(c"monolith")
            .engine_name(c"monolith")
            .api_version(vk::API_VERSION_1_3);
        let wanted = std::env::var("MONOLITH_VK_DEVICE").ok();
        let mut env = node.map(driver_env).unwrap_or_default();
        let (instance, physical, queue_family, name) = loop {
            for (var, value) in &env {
                // SAFETY: the compositor creates its renderer before starting any
                // other thread, so nothing reads the environment concurrently.
                unsafe { std::env::set_var(var, value) };
            }
            let instance = unsafe {
                entry.create_instance(
                    &vk::InstanceCreateInfo::default().application_info(&app),
                    None,
                )
            };
            for (var, _) in &env {
                // SAFETY: as above. Removing them keeps clients from inheriting them.
                unsafe { std::env::remove_var(var) };
            }
            let instance = match instance {
                Ok(i) => i,
                Err(_) if !std::mem::take(&mut env).is_empty() => continue,
                Err(e) => return Err(e.into()),
            };
            match unsafe { pick_physical(&instance, wanted.as_deref(), node) } {
                Some((p, f, n)) => break (instance, p, f, n),
                None => {
                    unsafe { instance.destroy_instance(None) };
                    if std::mem::take(&mut env).is_empty() {
                        return Err(Error::NoSuitableDevice);
                    }
                }
            }
        };
        let priorities = [1.0];
        let available: Vec<_> = unsafe { instance.enumerate_device_extension_properties(physical) }
            .unwrap_or_default()
            .iter()
            .filter_map(|e| e.extension_name_as_c_str().ok().map(ToOwned::to_owned))
            .collect();
        let drm_node = available
            .iter()
            .any(|a| a.as_c_str() == ash::ext::physical_device_drm::NAME)
            .then(|| unsafe { drm_node(&instance, physical) })
            .flatten();
        let has_dmabuf = DMABUF_EXTENSIONS
            .iter()
            .all(|n| available.iter().any(|a| a.as_c_str() == *n));
        let mut extensions = vec![ash::khr::push_descriptor::NAME.as_ptr()];
        if has_dmabuf {
            extensions.extend(DMABUF_EXTENSIONS.iter().map(|n| n.as_ptr()));
        }
        let global_priority = [
            ash::khr::global_priority::NAME,
            ash::ext::global_priority::NAME,
        ]
        .into_iter()
        .find(|n| available.iter().any(|a| a.as_c_str() == *n));
        let mut priorities_to_try = vec![None];
        if let Some(name) = global_priority {
            extensions.push(name.as_ptr());
            priorities_to_try = vec![
                Some(vk::QueueGlobalPriorityKHR::REALTIME),
                Some(vk::QueueGlobalPriorityKHR::HIGH),
                None,
            ];
        }
        let mut created = Err(vk::Result::ERROR_INITIALIZATION_FAILED);
        for priority in priorities_to_try {
            let mut features13 = vk::PhysicalDeviceVulkan13Features::default()
                .dynamic_rendering(true)
                .synchronization2(true);
            let mut global = vk::DeviceQueueGlobalPriorityCreateInfoKHR::default()
                .global_priority(priority.unwrap_or(vk::QueueGlobalPriorityKHR::MEDIUM));
            let mut queue = vk::DeviceQueueCreateInfo::default()
                .queue_family_index(queue_family)
                .queue_priorities(&priorities);
            if priority.is_some() {
                queue = queue.push_next(&mut global);
            }
            let queues = [queue];
            let info = vk::DeviceCreateInfo::default()
                .queue_create_infos(&queues)
                .enabled_extension_names(&extensions)
                .push_next(&mut features13);
            created = unsafe { instance.create_device(physical, &info, None) };
            match &created {
                Ok(_) => {
                    tracing::info!(?priority, "queue global priority");
                    break;
                }
                Err(e) => tracing::debug!(?priority, "queue global priority refused: {e}"),
            }
        }
        let device = match created {
            Ok(d) => d,
            Err(e) => {
                unsafe { instance.destroy_instance(None) };
                return Err(e.into());
            }
        };
        let queue = unsafe { device.get_device_queue(queue_family, 0) };
        let push_descriptor = ash::khr::push_descriptor::Device::new(&instance, &device);
        let dmabuf = has_dmabuf.then(|| DmabufExt {
            memory_fd: ash::khr::external_memory_fd::Device::new(&instance, &device),
            fence_fd: ash::khr::external_fence_fd::Device::new(&instance, &device),
            modifier: ash::ext::image_drm_format_modifier::Device::new(&instance, &device),
        });
        let allocator = Allocator::new(&AllocatorCreateDesc {
            instance: instance.clone(),
            device: device.clone(),
            physical_device: physical,
            debug_settings: Default::default(),
            buffer_device_address: false,
            // Host blocks are pinned system RAM that stays resident while any
            // allocation lives in them, and the default 64 MB block is mostly idle.
            allocation_sizes: AllocationSizes::new(256 << 20, 4 << 20),
        });
        let device = Device {
            _entry: entry,
            instance,
            physical,
            device,
            queue: Mutex::new(queue),
            queue_family,
            push_descriptor,
            dmabuf,
            name,
            drm_node,
            spare_fences: Mutex::new(Vec::new()),
        };
        Ok(Self {
            staging_pool: Mutex::new(Vec::new()),
            allocator: Mutex::new(allocator?),
            device,
        })
    }
}

/// Whether `physical` is the device behind DRM device number `node`, as its
/// primary or render node.
unsafe fn serves_node(instance: &ash::Instance, physical: vk::PhysicalDevice, node: u64) -> bool {
    let mut drm = vk::PhysicalDeviceDrmPropertiesEXT::default();
    let mut props = vk::PhysicalDeviceProperties2::default().push_next(&mut drm);
    unsafe { instance.get_physical_device_properties2(physical, &mut props) };
    let (major, minor) = (
        rustix::fs::major(node) as i64,
        rustix::fs::minor(node) as i64,
    );
    (drm.has_primary == vk::TRUE && (drm.primary_major, drm.primary_minor) == (major, minor))
        || (drm.has_render == vk::TRUE && (drm.render_major, drm.render_minor) == (major, minor))
}

/// Variables set only while the instance is created, unless the user already
/// picks drivers themselves. The loader keeps every ICD it finds loaded for the
/// instance's lifetime, on NixOS including lavapipe and 26 MB of resident
/// libLLVM. Without an X server NVIDIA's ICD also initialises through glvnd's
/// libEGL, which loads every EGL vendor, and Mesa's pulls in LLVM again.
fn driver_env(node: u64) -> Vec<(&'static str, std::ffi::OsString)> {
    let set = |vars: &[&str]| vars.iter().any(|v| std::env::var_os(v).is_some());
    let (major, minor) = (rustix::fs::major(node), rustix::fs::minor(node));
    let Ok(driver) = std::fs::read_link(format!("/sys/dev/char/{major}:{minor}/device/driver"))
    else {
        return Vec::new();
    };
    let driver = driver.file_name().and_then(|d| d.to_str()).unwrap_or_default();
    let mut env = Vec::new();
    let glob = match driver {
        "nvidia" => Some("*nvidia*"),
        "amdgpu" | "radeon" => Some("*radeon*"),
        "i915" | "xe" => Some("*intel*"),
        "nouveau" => Some("*nouveau*"),
        _ => None,
    };
    let loader = [
        "VK_LOADER_DRIVERS_SELECT",
        "VK_LOADER_DRIVERS_DISABLE",
        "VK_DRIVER_FILES",
        "VK_ICD_FILENAMES",
        "VK_ADD_DRIVER_FILES",
    ];
    if let Some(glob) = glob
        && !set(&loader)
    {
        env.push(("VK_LOADER_DRIVERS_SELECT", glob.into()));
    }
    let glvnd = ["__EGL_VENDOR_LIBRARY_FILENAMES", "__EGL_VENDOR_LIBRARY_DIRS"];
    if driver == "nvidia"
        && !set(&glvnd)
        && let Some(vendor) = nvidia_egl_vendor()
    {
        env.push(("__EGL_VENDOR_LIBRARY_FILENAMES", vendor.into()));
    }
    env
}

/// NVIDIA's glvnd EGL vendor file, from glvnd's default search path.
fn nvidia_egl_vendor() -> Option<std::path::PathBuf> {
    [
        "/run/opengl-driver/share/glvnd/egl_vendor.d",
        "/etc/glvnd/egl_vendor.d",
        "/usr/share/glvnd/egl_vendor.d",
    ]
    .into_iter()
    .filter_map(|dir| std::fs::read_dir(dir).ok())
    .flatten()
    .filter_map(Result::ok)
    .map(|e| e.path())
    .find(|p| {
        p.extension().is_some_and(|e| e == "json")
            && p.file_name()
                .and_then(|n| n.to_str())
                .is_some_and(|n| n.contains("nvidia"))
    })
}

/// The render node of `physical`, or its primary node when it has none.
unsafe fn drm_node(instance: &ash::Instance, physical: vk::PhysicalDevice) -> Option<u64> {
    let mut drm = vk::PhysicalDeviceDrmPropertiesEXT::default();
    let mut props = vk::PhysicalDeviceProperties2::default().push_next(&mut drm);
    unsafe { instance.get_physical_device_properties2(physical, &mut props) };
    let node = |major: i64, minor: i64| rustix::fs::makedev(major as u32, minor as u32);
    if drm.has_render == vk::TRUE {
        Some(node(drm.render_major, drm.render_minor))
    } else if drm.has_primary == vk::TRUE {
        Some(node(drm.primary_major, drm.primary_minor))
    } else {
        None
    }
}

unsafe fn pick_physical(
    instance: &ash::Instance,
    wanted: Option<&str>,
    node: Option<u64>,
) -> Option<(vk::PhysicalDevice, u32, String)> {
    let devices = unsafe { instance.enumerate_physical_devices() }.ok()?;
    let mut candidates = Vec::new();
    for physical in devices {
        let props = unsafe { instance.get_physical_device_properties(physical) };
        if props.api_version < vk::API_VERSION_1_3 {
            continue;
        }
        let name = props
            .device_name_as_c_str()
            .unwrap_or(c"unknown")
            .to_string_lossy()
            .into_owned();
        if wanted.is_some_and(|w| !name.contains(w)) {
            continue;
        }
        let mut f13 = vk::PhysicalDeviceVulkan13Features::default();
        let mut f2 = vk::PhysicalDeviceFeatures2::default().push_next(&mut f13);
        unsafe { instance.get_physical_device_features2(physical, &mut f2) };
        if f13.dynamic_rendering == vk::FALSE || f13.synchronization2 == vk::FALSE {
            continue;
        }
        let extensions =
            unsafe { instance.enumerate_device_extension_properties(physical) }.unwrap_or_default();
        let has = |n: &std::ffi::CStr| {
            extensions
                .iter()
                .any(|e| e.extension_name_as_c_str().ok() == Some(n))
        };
        if !has(ash::khr::push_descriptor::NAME) {
            continue;
        }
        if let Some(node) = node
            && !(has(ash::ext::physical_device_drm::NAME)
                && unsafe { serves_node(instance, physical, node) })
        {
            continue;
        }
        let families = unsafe { instance.get_physical_device_queue_family_properties(physical) };
        let Some(family) = families
            .iter()
            .position(|f| f.queue_flags.contains(vk::QueueFlags::GRAPHICS))
        else {
            continue;
        };
        let rank = match props.device_type {
            vk::PhysicalDeviceType::DISCRETE_GPU => 0,
            vk::PhysicalDeviceType::INTEGRATED_GPU => 1,
            vk::PhysicalDeviceType::VIRTUAL_GPU => 2,
            _ => 3,
        };
        candidates.push((rank, physical, family as u32, name));
    }
    candidates.sort_by_key(|c| c.0);
    candidates.into_iter().next().map(|(_, p, f, n)| (p, f, n))
}

1	use crate::Error;
2	use ash::vk;
3	use gpu_allocator::AllocationSizes;
4	use gpu_allocator::vulkan::{Allocator, AllocatorCreateDesc};
5	use std::sync::Mutex;
6
7	/// Everything that must outlive every Vulkan object the renderer hands out.
8	/// Fields drop in declaration order, so the allocator frees its memory before
9	/// the device is destroyed.
10	pub(crate) struct Shared {
11	/// Staging buffers kept for reuse, see `Staging`.
12	pub staging_pool: Mutex<Vec<crate::image::Pooled>>,
13	pub allocator: Mutex<Allocator>,
14	pub device: Device,
15	}
16
17	impl Drop for Shared {
18	fn drop(&mut self) {
19	let pool = std::mem::take(
20	self.staging_pool
21	.get_mut()
22	.unwrap_or_else(\|e\| e.into_inner()),
23	);
24	let allocator = self.allocator.get_mut().unwrap_or_else(\|e\| e.into_inner());
25	for p in pool {
26	unsafe { self.device.device.destroy_buffer(p.buffer, None) };
27	let _ = allocator.free(p.allocation);
28	}
29	}
30	}
31
32	/// Loaders for the extensions that dmabuf import, export and fence export
33	/// need. Absent when the device lacks any of them.
34	pub(crate) struct DmabufExt {
35	pub memory_fd: ash::khr::external_memory_fd::Device,
36	pub fence_fd: ash::khr::external_fence_fd::Device,
37	pub modifier: ash::ext::image_drm_format_modifier::Device,
38	}
39
40	const DMABUF_EXTENSIONS: [&std::ffi::CStr; 5] = [
41	ash::khr::external_memory_fd::NAME,
42	ash::ext::external_memory_dma_buf::NAME,
43	ash::ext::image_drm_format_modifier::NAME,
44	ash::ext::queue_family_foreign::NAME,
45	ash::khr::external_fence_fd::NAME,
46	];
47
48	pub(crate) struct Device {
49	pub _entry: ash::Entry,
50	pub instance: ash::Instance,
51	pub physical: vk::PhysicalDevice,
52	pub device: ash::Device,
53	pub queue: Mutex<vk::Queue>,
54	pub queue_family: u32,
55	pub push_descriptor: ash::khr::push_descriptor::Device,
56	pub dmabuf: Option<DmabufExt>,
57	pub name: String,
58	pub drm_node: Option<u64>,
59	/// Signalled fences kept for reuse, see `FenceInner`.
60	pub spare_fences: Mutex<Vec<vk::Fence>>,
61	}
62
63	impl Drop for Device {
64	fn drop(&mut self) {
65	unsafe {
66	let _ = self.device.device_wait_idle();
67	for f in self
68	.spare_fences
69	.get_mut()
70	.unwrap_or_else(\|e\| e.into_inner())
71	.drain(..)
72	{
73	self.device.destroy_fence(f, None);
74	}
75	self.device.destroy_device(None);
76	self.instance.destroy_instance(None);
77	}
78	}
79	}
80
81	impl Shared {
82	/// Opens the first suitable device, or the one whose name contains
83	/// `MONOLITH_VK_DEVICE` when that is set. With `node`, only the device
84	/// behind that DRM device number qualifies.
85	pub fn new(node: Option<u64>) -> Result<Self, Error> {
86	let entry = unsafe { ash::Entry::load()? };
87	let app = vk::ApplicationInfo::default()
88	.application_name(c"monolith")
89	.engine_name(c"monolith")
90	.api_version(vk::API_VERSION_1_3);
91	let wanted = std::env::var("MONOLITH_VK_DEVICE").ok();
92	let mut env = node.map(driver_env).unwrap_or_default();
93	let (instance, physical, queue_family, name) = loop {
94	for (var, value) in &env {
95	// SAFETY: the compositor creates its renderer before starting any
96	// other thread, so nothing reads the environment concurrently.
97	unsafe { std::env::set_var(var, value) };
98	}
99	let instance = unsafe {
100	entry.create_instance(
101	&vk::InstanceCreateInfo::default().application_info(&app),
102	None,
103	)
104	};
105	for (var, _) in &env {
106	// SAFETY: as above. Removing them keeps clients from inheriting them.
107	unsafe { std::env::remove_var(var) };
108	}
109	let instance = match instance {
110	Ok(i) => i,
111	Err(_) if !std::mem::take(&mut env).is_empty() => continue,
112	Err(e) => return Err(e.into()),
113	};
114	match unsafe { pick_physical(&instance, wanted.as_deref(), node) } {
115	Some((p, f, n)) => break (instance, p, f, n),
116	None => {
117	unsafe { instance.destroy_instance(None) };
118	if std::mem::take(&mut env).is_empty() {
119	return Err(Error::NoSuitableDevice);
120	}
121	}
122	}
123	};
124	let priorities = [1.0];
125	let available: Vec<_> = unsafe { instance.enumerate_device_extension_properties(physical) }
126	.unwrap_or_default()
127	.iter()
128	.filter_map(\|e\| e.extension_name_as_c_str().ok().map(ToOwned::to_owned))
129	.collect();
130	let drm_node = available
131	.iter()
132	.any(\|a\| a.as_c_str() == ash::ext::physical_device_drm::NAME)
133	.then(\|\| unsafe { drm_node(&instance, physical) })
134	.flatten();
135	let has_dmabuf = DMABUF_EXTENSIONS
136	.iter()
137	.all(\|n\| available.iter().any(\|a\| a.as_c_str() == *n));
138	let mut extensions = vec![ash::khr::push_descriptor::NAME.as_ptr()];
139	if has_dmabuf {
140	extensions.extend(DMABUF_EXTENSIONS.iter().map(\|n\| n.as_ptr()));
141	}
142	let global_priority = [
143	ash::khr::global_priority::NAME,
144	ash::ext::global_priority::NAME,
145	]
146	.into_iter()
147	.find(\|n\| available.iter().any(\|a\| a.as_c_str() == *n));
148	let mut priorities_to_try = vec![None];
149	if let Some(name) = global_priority {
150	extensions.push(name.as_ptr());
151	priorities_to_try = vec![
152	Some(vk::QueueGlobalPriorityKHR::REALTIME),
153	Some(vk::QueueGlobalPriorityKHR::HIGH),
154	None,
155	];
156	}
157	let mut created = Err(vk::Result::ERROR_INITIALIZATION_FAILED);
158	for priority in priorities_to_try {
159	let mut features13 = vk::PhysicalDeviceVulkan13Features::default()
160	.dynamic_rendering(true)
161	.synchronization2(true);
162	let mut global = vk::DeviceQueueGlobalPriorityCreateInfoKHR::default()
163	.global_priority(priority.unwrap_or(vk::QueueGlobalPriorityKHR::MEDIUM));
164	let mut queue = vk::DeviceQueueCreateInfo::default()
165	.queue_family_index(queue_family)
166	.queue_priorities(&priorities);
167	if priority.is_some() {
168	queue = queue.push_next(&mut global);
169	}
170	let queues = [queue];
171	let info = vk::DeviceCreateInfo::default()
172	.queue_create_infos(&queues)
173	.enabled_extension_names(&extensions)
174	.push_next(&mut features13);
175	created = unsafe { instance.create_device(physical, &info, None) };
176	match &created {
177	Ok(_) => {
178	tracing::info!(?priority, "queue global priority");
179	break;
180	}
181	Err(e) => tracing::debug!(?priority, "queue global priority refused: {e}"),
182	}
183	}
184	let device = match created {
185	Ok(d) => d,
186	Err(e) => {
187	unsafe { instance.destroy_instance(None) };
188	return Err(e.into());
189	}
190	};
191	let queue = unsafe { device.get_device_queue(queue_family, 0) };
192	let push_descriptor = ash::khr::push_descriptor::Device::new(&instance, &device);
193	let dmabuf = has_dmabuf.then(\|\| DmabufExt {
194	memory_fd: ash::khr::external_memory_fd::Device::new(&instance, &device),
195	fence_fd: ash::khr::external_fence_fd::Device::new(&instance, &device),
196	modifier: ash::ext::image_drm_format_modifier::Device::new(&instance, &device),
197	});
198	let allocator = Allocator::new(&AllocatorCreateDesc {
199	instance: instance.clone(),
200	device: device.clone(),
201	physical_device: physical,
202	debug_settings: Default::default(),
203	buffer_device_address: false,
204	// Host blocks are pinned system RAM that stays resident while any
205	// allocation lives in them, and the default 64 MB block is mostly idle.
206	allocation_sizes: AllocationSizes::new(256 << 20, 4 << 20),
207	});
208	let device = Device {
209	_entry: entry,
210	instance,
211	physical,
212	device,
213	queue: Mutex::new(queue),
214	queue_family,
215	push_descriptor,
216	dmabuf,
217	name,
218	drm_node,
219	spare_fences: Mutex::new(Vec::new()),
220	};
221	Ok(Self {
222	staging_pool: Mutex::new(Vec::new()),
223	allocator: Mutex::new(allocator?),
224	device,
225	})
226	}
227	}
228
229	/// Whether `physical` is the device behind DRM device number `node`, as its
230	/// primary or render node.
231	unsafe fn serves_node(instance: &ash::Instance, physical: vk::PhysicalDevice, node: u64) -> bool {
232	let mut drm = vk::PhysicalDeviceDrmPropertiesEXT::default();
233	let mut props = vk::PhysicalDeviceProperties2::default().push_next(&mut drm);
234	unsafe { instance.get_physical_device_properties2(physical, &mut props) };
235	let (major, minor) = (
236	rustix::fs::major(node) as i64,
237	rustix::fs::minor(node) as i64,
238	);
239	(drm.has_primary == vk::TRUE && (drm.primary_major, drm.primary_minor) == (major, minor))
240	\|\| (drm.has_render == vk::TRUE && (drm.render_major, drm.render_minor) == (major, minor))
241	}
242
243	/// Variables set only while the instance is created, unless the user already
244	/// picks drivers themselves. The loader keeps every ICD it finds loaded for the
245	/// instance's lifetime, on NixOS including lavapipe and 26 MB of resident
246	/// libLLVM. Without an X server NVIDIA's ICD also initialises through glvnd's
247	/// libEGL, which loads every EGL vendor, and Mesa's pulls in LLVM again.
248	fn driver_env(node: u64) -> Vec<(&'static str, std::ffi::OsString)> {
249	let set = \|vars: &[&str]\| vars.iter().any(\|v\| std::env::var_os(v).is_some());
250	let (major, minor) = (rustix::fs::major(node), rustix::fs::minor(node));
251	let Ok(driver) = std::fs::read_link(format!("/sys/dev/char/{major}:{minor}/device/driver"))
252	else {
253	return Vec::new();
254	};
255	let driver = driver.file_name().and_then(\|d\| d.to_str()).unwrap_or_default();
256	let mut env = Vec::new();
257	let glob = match driver {
258	"nvidia" => Some("nvidia"),
259	"amdgpu" \| "radeon" => Some("radeon"),
260	"i915" \| "xe" => Some("intel"),
261	"nouveau" => Some("nouveau"),
262	_ => None,
263	};
264	let loader = [
265	"VK_LOADER_DRIVERS_SELECT",
266	"VK_LOADER_DRIVERS_DISABLE",
267	"VK_DRIVER_FILES",
268	"VK_ICD_FILENAMES",
269	"VK_ADD_DRIVER_FILES",
270	];
271	if let Some(glob) = glob
272	&& !set(&loader)
273	{
274	env.push(("VK_LOADER_DRIVERS_SELECT", glob.into()));
275	}
276	let glvnd = ["__EGL_VENDOR_LIBRARY_FILENAMES", "__EGL_VENDOR_LIBRARY_DIRS"];
277	if driver == "nvidia"
278	&& !set(&glvnd)
279	&& let Some(vendor) = nvidia_egl_vendor()
280	{
281	env.push(("__EGL_VENDOR_LIBRARY_FILENAMES", vendor.into()));
282	}
283	env
284	}
285
286	/// NVIDIA's glvnd EGL vendor file, from glvnd's default search path.
287	fn nvidia_egl_vendor() -> Option<std::path::PathBuf> {
288	[
289	"/run/opengl-driver/share/glvnd/egl_vendor.d",
290	"/etc/glvnd/egl_vendor.d",
291	"/usr/share/glvnd/egl_vendor.d",
292	]
293	.into_iter()
294	.filter_map(\|dir\| std::fs::read_dir(dir).ok())
295	.flatten()
296	.filter_map(Result::ok)
297	.map(\|e\| e.path())
298	.find(\|p\| {
299	p.extension().is_some_and(\|e\| e == "json")
300	&& p.file_name()
301	.and_then(\|n\| n.to_str())
302	.is_some_and(\|n\| n.contains("nvidia"))
303	})
304	}
305
306	/// The render node of `physical`, or its primary node when it has none.
307	unsafe fn drm_node(instance: &ash::Instance, physical: vk::PhysicalDevice) -> Option<u64> {
308	let mut drm = vk::PhysicalDeviceDrmPropertiesEXT::default();
309	let mut props = vk::PhysicalDeviceProperties2::default().push_next(&mut drm);
310	unsafe { instance.get_physical_device_properties2(physical, &mut props) };
311	let node = \|major: i64, minor: i64\| rustix::fs::makedev(major as u32, minor as u32);
312	if drm.has_render == vk::TRUE {
313	Some(node(drm.render_major, drm.render_minor))
314	} else if drm.has_primary == vk::TRUE {
315	Some(node(drm.primary_major, drm.primary_minor))
316	} else {
317	None
318	}
319	}
320
321	unsafe fn pick_physical(
322	instance: &ash::Instance,
323	wanted: Option<&str>,
324	node: Option<u64>,
325	) -> Option<(vk::PhysicalDevice, u32, String)> {
326	let devices = unsafe { instance.enumerate_physical_devices() }.ok()?;
327	let mut candidates = Vec::new();
328	for physical in devices {
329	let props = unsafe { instance.get_physical_device_properties(physical) };
330	if props.api_version < vk::API_VERSION_1_3 {
331	continue;
332	}
333	let name = props
334	.device_name_as_c_str()
335	.unwrap_or(c"unknown")
336	.to_string_lossy()
337	.into_owned();
338	if wanted.is_some_and(\|w\| !name.contains(w)) {
339	continue;
340	}
341	let mut f13 = vk::PhysicalDeviceVulkan13Features::default();
342	let mut f2 = vk::PhysicalDeviceFeatures2::default().push_next(&mut f13);
343	unsafe { instance.get_physical_device_features2(physical, &mut f2) };
344	if f13.dynamic_rendering == vk::FALSE \|\| f13.synchronization2 == vk::FALSE {
345	continue;
346	}
347	let extensions =
348	unsafe { instance.enumerate_device_extension_properties(physical) }.unwrap_or_default();
349	let has = \|n: &std::ffi::CStr\| {
350	extensions
351	.iter()
352	.any(\|e\| e.extension_name_as_c_str().ok() == Some(n))
353	};
354	if !has(ash::khr::push_descriptor::NAME) {
355	continue;
356	}
357	if let Some(node) = node
358	&& !(has(ash::ext::physical_device_drm::NAME)
359	&& unsafe { serves_node(instance, physical, node) })
360	{
361	continue;
362	}
363	let families = unsafe { instance.get_physical_device_queue_family_properties(physical) };
364	let Some(family) = families
365	.iter()
366	.position(\|f\| f.queue_flags.contains(vk::QueueFlags::GRAPHICS))
367	else {
368	continue;
369	};
370	let rank = match props.device_type {
371	vk::PhysicalDeviceType::DISCRETE_GPU => 0,
372	vk::PhysicalDeviceType::INTEGRATED_GPU => 1,
373	vk::PhysicalDeviceType::VIRTUAL_GPU => 2,
374	_ => 3,
375	};
376	candidates.push((rank, physical, family as u32, name));
377	}
378	candidates.sort_by_key(\|c\| c.0);
379	candidates.into_iter().next().map(\|(_, p, f, n)\| (p, f, n))
380	}