linux.git/rust/kernel/drm/driver.rs, branch v7.3-rc2

rust: drm: Fix typo in FEAT_RENDER documentation

2026-07-13T16:13:26+00:00

Correct the spelling of "privilege" in the DRIVER_RENDER Rustdoc.

Signed-off-by: Younes Akhouayri 
Reviewed-by: Alice Ryhl 
Link: https://patch.msgid.link/20260712-docs-drm-feat-render-rustdoc-typo-v1-1-c9df1cbbce4b@younes.io
Signed-off-by: Danilo Krummrich

rust: drm: Add RegistrationData to drm::Driver

2026-07-12T14:05:44+00:00

Add a RegistrationData GAT (Generic Associated Type) to drm::Driver.
The lifetime parameter is tied to the parent bus device binding scope.
Registration<'a, T> takes ownership of the data via Pin>,
storing it with its real lifetime. The pointer is written to drm::Device
before drm_dev_register() to ensure it is already in place when ioctls
arrive.

Device::registration_data_with() provides access with the
lifetime shortened from 'static via a pointer cast. Since
Registration::drop() calls drm_dev_unplug(), which performs an SRCU
barrier waiting for all drm_dev_enter() critical sections to complete,
the data is guaranteed to remain valid for the duration of any
RegistrationGuard.

Reviewed-by: Lyude Paul 
Tested-by: Deborah Brouwer 
Link: https://patch.msgid.link/20260628145406.2107056-18-dakr@kernel.org
[ Move registration_data_unchecked() to Device impl
  block. - Danilo ]
Signed-off-by: Danilo Krummrich

rust: drm: return ParentDevice from Device AsRef

2026-07-12T14:01:06+00:00

Change AsRef for drm::Device to return &T::ParentDevice
instead of &device::Device, and restrict it to the Normal context.
Device still gets this through Deref coercion.

This provides access to the typed parent bus device rather than the raw
base device.

Reviewed-by: Lyude Paul 
Reviewed-by: Alexandre Courbot 
Tested-by: Deborah Brouwer 
Link: https://patch.msgid.link/20260628145406.2107056-15-dakr@kernel.org
Signed-off-by: Danilo Krummrich

rust: drm: Add RegistrationGuard for drm_dev_enter/exit critical sections

2026-07-12T13:56:52+00:00

DRM ioctls do not guarantee that the parent bus device is still bound.
However, since DRM device registration is managed through Devres, using
drm_dev_unplug() on unregistration ensures that between drm_dev_enter()
and drm_dev_exit() the parent device must be bound.

Add RegistrationGuard, a guard object representing a drm_dev_enter/exit
SRCU critical section that dereferences to &Device. The
guard is obtained from Device and proves at runtime that the
device is still registered.

Switch Registration::drop from drm_dev_unregister() to drm_dev_unplug()
to provide the SRCU barrier that RegistrationGuard's safety argument
relies on.

Reviewed-by: Lyude Paul 
Reviewed-by: Alexandre Courbot 
Tested-by: Deborah Brouwer 
Link: https://patch.msgid.link/20260628145406.2107056-13-dakr@kernel.org
Signed-off-by: Danilo Krummrich

rust: drm: restrict AlwaysRefCounted to Normal GEM Object context

2026-07-12T13:56:52+00:00

Restrict AlwaysRefCounted for gem::Object and gem::shmem::Object to the
Normal context, since only Normal objects should be independently
reference-counted.

To avoid cascading through IntoGEMObject (which had AlwaysRefCounted as
a supertrait), remove AlwaysRefCounted from IntoGEMObject's supertraits
and instead add it as an explicit bound on lookup_handle(), which is the
only BaseObject method that returns an ARef.

Since Object::new() and shmem::Object::new() return ARef, move
them to Normal-only impl blocks. Similarly, simplify ObjectConfig and
shmem's parent_resv_obj field to the Normal context.

Remove the DeviceContext generic from DriverObject::new() and
Driver::Object, since GEM objects can only be constructed in the Normal
context. Simplify DriverAllocImpl accordingly.

Reviewed-by: Lyude Paul 
Reviewed-by: Alexandre Courbot 
Tested-by: Deborah Brouwer 
Link: https://patch.msgid.link/20260628145406.2107056-8-dakr@kernel.org
Signed-off-by: Danilo Krummrich

rust: drm: Add Driver::ParentDevice associated type

2026-07-12T13:56:52+00:00

Add a ParentDevice associated type to the Driver trait, allowing each
DRM driver to declare its parent bus device type (e.g.
auxiliary::Device, platform::Device).

Change UnregisteredDevice::new() to take &T::ParentDevice,
ensuring at the type level that the DRM device's parent matches the
declared bus device type.

Reviewed-by: Lyude Paul 
Reviewed-by: Alexandre Courbot 
Tested-by: Deborah Brouwer 
Link: https://patch.msgid.link/20260628145406.2107056-5-dakr@kernel.org
Signed-off-by: Danilo Krummrich

rust/drm/gem: Use DeviceContext with GEM objects

2026-06-02T20:51:16+00:00

Now that we have the ability to represent the context in which a DRM device
is in at compile-time, we can start carrying around this context with GEM
object types in order to allow a driver to safely create GEM objects before
a DRM device has registered with userspace.

Signed-off-by: Lyude Paul 
Reviewed-by: Daniel Almeida 
Link: https://patch.msgid.link/20260507220044.3204919-4-lyude@redhat.com
Signed-off-by: Danilo Krummrich

rust/drm: Introduce DeviceContext

2026-06-02T19:35:25+00:00

One of the tricky things about DRM bindings in Rust is the fact that
initialization of a DRM device is a multi-step process. It's quite normal
for a device driver to start making use of its DRM device for tasks like
creating GEM objects before userspace registration happens. This is an
issue in rust though, since prior to userspace registration the device is
only partly initialized. This means there's a plethora of DRM device
operations we can't yet expose without opening up the door to UB if the DRM
device in question isn't yet registered.

Additionally, this isn't something we can reliably check at runtime. And
even if we could, performing an operation which requires the device be
registered when the device isn't actually registered is a programmer bug,
meaning there's no real way to gracefully handle such a mistake at runtime.
And even if that wasn't the case, it would be horrendously annoying and
noisy to have to check if a device is registered constantly throughout a
driver.

In order to solve this, we first take inspiration from
`kernel::device::DeviceContext` and introduce `kernel::drm::DeviceContext`.
This provides us with a ZST type that we can generalize over to represent
contexts where a device is known to have been registered with userspace at
some point in time (`Registered`), along with contexts where we can't make
such a guarantee (`Uninit`).

It's important to note we intentionally do not provide a `DeviceContext`
which represents an unregistered device. This is because there's no
reasonable way to guarantee that a device with long-living references to
itself will not be registered eventually with userspace. Instead, we
provide a new-type for this: `UnregisteredDevice` which can
provide a guarantee that the `Device` has never been registered with
userspace. To ensure this, we modify `Registration` so that creating a new
`Registration` requires passing ownership of an `UnregisteredDevice`.

Signed-off-by: Lyude Paul 
Reviewed-by: Daniel Almeida 
Link: https://patch.msgid.link/20260507220044.3204919-2-lyude@redhat.com
Signed-off-by: Danilo Krummrich

rust: drm: add FEAT_RENDER flag for render node support

2026-05-28T22:19:04+00:00

Add FEAT_RENDER bool constant to the Driver trait to control
render node support. When enabled, the driver exposes /dev/dri/renderDXX
render nodes to userspace. The flag defaults to false, drivers can opt
in by setting it to true in their Driver implementation.

This is then enabled in the Tyr driver, while it's left disabled for
Nova for the time being.

Co-developed-by: Daniel Almeida 
Signed-off-by: Daniel Almeida 
Reviewed-by: Alice Ryhl 
Signed-off-by: Laura Nao 
Link: https://patch.msgid.link/20260507080914.95478-2-laura.nao@collabora.com
Signed-off-by: Danilo Krummrich

rust/drm: Remove imports covered by prelude::*

2026-02-24T15:11:41+00:00

This just removes any explicit imports of items in files that are already
being pulled in by `use prelude::*;`.

There should be no functional changes in this patch.

Signed-off-by: Lyude Paul 
Link: https://patch.msgid.link/20260122214316.3281257-2-lyude@redhat.com
Signed-off-by: Danilo Krummrich