drm/amd/display: Try RGB before YCbCr 4:4:4 in stream validationgrafted

amdgpu_dm_create_validate_stream_for_sink() walks encoding_order[] and
uses the first encoding that validates. YCbCr 4:4:4 is listed before
RGB, so an HDMI sink that advertises 4:4:4 gets YCbCr 4:4:4 whenever the
"color format" property is left at AUTO, even though RGB fits the same
link.

That contradicts the documented AUTO behaviour for HDMI in enum
drm_connector_color_format (RGB, falling back to YCbCr 4:2:0 only when
the bandwidth is not available or the mode is 4:2:0-only), which the
amdgpu implementation of the property also describes. It also leaves
the "Broadcast RGB" property without effect on such sinks, since the
quantization range it selects only applies to RGB output.

Try RGB first. The mask still holds every encoding the sink supports,
so a mode that cannot carry RGB falls back exactly as before.

For reference, v7.2 picked RGB here unless YCbCr 4:4:4 was forced
through debugfs, while earlier kernels picked YCbCr 4:4:4 for any HDMI
sink that advertised it.

Fixes: 0b0ff65d3ca1 ("drm/amd/display: Refactor stream validation")
Suggested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Assisted-by: Claude Code:claude-fable-5-1
Signed-off-by: Adrian Betschart <adrian.betschart@cinemaone.ch>
Reviewed-by: Fangzhi Zuo <jerry.zuo@amd.com>
Tested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 7de432bc753133764dc40d37f9388da56de251e7)

6 files changed, 253 insertions, 0 deletions

diff --git a/drivers/gpu/drm/nova/Kconfig b/drivers/gpu/drm/nova/Kconfig
new file mode 100644
index 000000000..ba16c7440
--- /dev/null
+++ b/drivers/gpu/drm/nova/Kconfig
@@ -0,0 +1,17 @@
+config DRM_NOVA
+	tristate "Nova DRM driver"
+	depends on 64BIT
+	depends on DRM=y
+	depends on PCI
+	depends on RUST
+	depends on !CPU_BIG_ENDIAN
+	select AUXILIARY_BUS
+	select NOVA_CORE
+	default n
+	help
+	  Choose this if you want to build the Nova DRM driver for Nvidia
+	  GSP-based GPUs.
+
+	  This driver is work in progress and may not be functional.
+
+	  If M is selected, the module will be called nova-drm.
diff --git a/drivers/gpu/drm/nova/Makefile b/drivers/gpu/drm/nova/Makefile
new file mode 100644
index 000000000..6355f7502
--- /dev/null
+++ b/drivers/gpu/drm/nova/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+# nova-drm is built from drivers/gpu/Makefile.
+# nova.o (rust-analyzer marker - DO NOT REMOVE).
diff --git a/drivers/gpu/drm/nova/driver.rs b/drivers/gpu/drm/nova/driver.rs
new file mode 100644
index 000000000..60752bccd
--- /dev/null
+++ b/drivers/gpu/drm/nova/driver.rs
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use kernel::{
+    auxiliary,
+    device::{
+        Core,
+        DeviceContext, //
+    },
+    drm::{
+        self,
+        gem,
+        ioctl, //
+    },
+    prelude::*,
+    sync::aref::ARef, //
+};
+
+use crate::file::File;
+use crate::gem::NovaObject;
+
+pub(crate) struct NovaDriver;
+
+pub(crate) struct Nova<'bound> {
+    #[expect(unused)]
+    drm: ARef<drm::Device<NovaDriver>>,
+    _reg: drm::Registration<'bound, NovaDriver>,
+}
+
+/// Convienence type alias for the DRM device type for this driver
+pub(crate) type NovaDevice<Ctx = drm::Normal> = drm::Device<NovaDriver, Ctx>;
+
+const INFO: drm::DriverInfo = drm::DriverInfo {
+    major: 0,
+    minor: 0,
+    patchlevel: 0,
+    name: c"nova-drm",
+    desc: c"NVIDIA Graphics and Compute",
+};
+
+const NOVA_CORE_MODULE_NAME: &CStr = c"nova-core";
+const AUXILIARY_NAME: &CStr = c"nova-drm";
+
+kernel::auxiliary_device_table!(
+    AUX_TABLE,
+    <NovaDriver as auxiliary::Driver>::IdInfo,
+    [(
+        auxiliary::DeviceId::new(NOVA_CORE_MODULE_NAME, AUXILIARY_NAME),
+        ()
+    )]
+);
+
+impl auxiliary::Driver for NovaDriver {
+    type IdInfo = ();
+    type Data<'bound> = Nova<'bound>;
+    const ID_TABLE: auxiliary::IdTable<Self::IdInfo> = &AUX_TABLE;
+
+    fn probe<'bound>(
+        adev: &'bound auxiliary::Device<Core<'_>>,
+        _info: &'bound Self::IdInfo,
+    ) -> impl PinInit<Self::Data<'bound>, Error> + 'bound {
+        let drm = drm::UnregisteredDevice::<Self>::new(adev, Ok(()))?;
+        // SAFETY: `reg` is stored in `Nova` and dropped when the driver is unbound; it is
+        // never forgotten.
+        let reg = unsafe { drm::Registration::new(adev.as_ref(), drm, (), 0)? };
+
+        Ok(Nova {
+            drm: reg.device().into(),
+            _reg: reg,
+        })
+    }
+}
+
+#[vtable]
+impl drm::Driver for NovaDriver {
+    type Data = ();
+    type RegistrationData<'a> = ();
+    type File = File;
+    type Object = gem::Object<NovaObject>;
+    type ParentDevice<Ctx: DeviceContext> = auxiliary::Device<Ctx>;
+
+    const INFO: drm::DriverInfo = INFO;
+
+    kernel::declare_drm_ioctls! {
+        (NOVA_GETPARAM, drm_nova_getparam, ioctl::RENDER_ALLOW, File::get_param),
+        (NOVA_GEM_CREATE, drm_nova_gem_create, ioctl::AUTH | ioctl::RENDER_ALLOW, File::gem_create),
+        (NOVA_GEM_INFO, drm_nova_gem_info, ioctl::AUTH | ioctl::RENDER_ALLOW, File::gem_info),
+    }
+}
diff --git a/drivers/gpu/drm/nova/file.rs b/drivers/gpu/drm/nova/file.rs
new file mode 100644
index 000000000..298c02bac
--- /dev/null
+++ b/drivers/gpu/drm/nova/file.rs
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use crate::driver::{NovaDevice, NovaDriver};
+use crate::gem::NovaObject;
+use kernel::{
+    alloc::flags::*,
+    auxiliary,
+    device::Bound,
+    drm::{
+        self,
+        gem::BaseObject,
+        Registered, //
+    },
+    pci,
+    prelude::*,
+    uapi,
+};
+
+pub(crate) struct File;
+
+impl drm::file::DriverFile for File {
+    type Driver = NovaDriver;
+
+    fn open(_dev: &NovaDevice) -> Result<Pin<KBox<Self>>> {
+        Ok(KBox::new(Self, GFP_KERNEL)?.into())
+    }
+}
+
+impl File {
+    /// IOCTL: get_param: Query GPU / driver metadata.
+    pub(crate) fn get_param(
+        dev: &NovaDevice<Registered>,
+        _reg_data: &(),
+        getparam: &mut uapi::drm_nova_getparam,
+        _file: &drm::File<File>,
+    ) -> Result<u32> {
+        let adev: &auxiliary::Device<Bound> = dev.as_ref();
+        let pdev: &pci::Device<Bound> = adev.parent().try_into()?;
+
+        let value = match getparam.param as u32 {
+            uapi::NOVA_GETPARAM_VRAM_BAR_SIZE => pdev.resource_len(1)?,
+            _ => return Err(EINVAL),
+        };
+
+        getparam.value = Into::<u64>::into(value);
+
+        Ok(0)
+    }
+
+    /// IOCTL: gem_create: Create a new DRM GEM object.
+    pub(crate) fn gem_create(
+        dev: &NovaDevice<Registered>,
+        _reg_data: &(),
+        req: &mut uapi::drm_nova_gem_create,
+        file: &drm::File<File>,
+    ) -> Result<u32> {
+        let obj = NovaObject::new(dev, req.size.try_into()?)?;
+
+        req.handle = obj.create_handle(file)?;
+
+        Ok(0)
+    }
+
+    /// IOCTL: gem_info: Query GEM metadata.
+    pub(crate) fn gem_info(
+        _dev: &NovaDevice<Registered>,
+        _reg_data: &(),
+        req: &mut uapi::drm_nova_gem_info,
+        file: &drm::File<File>,
+    ) -> Result<u32> {
+        let bo = NovaObject::lookup_handle(file, req.handle)?;
+
+        req.size = bo.size().try_into()?;
+
+        Ok(0)
+    }
+}
diff --git a/drivers/gpu/drm/nova/gem.rs b/drivers/gpu/drm/nova/gem.rs
new file mode 100644
index 000000000..2b6fe9dc0
--- /dev/null
+++ b/drivers/gpu/drm/nova/gem.rs
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use kernel::{
+    drm,
+    drm::{
+        gem,
+        gem::BaseObject, //
+    },
+    page,
+    prelude::*,
+    sync::aref::ARef,
+};
+
+use crate::{
+    driver::{NovaDevice, NovaDriver},
+    file::File,
+};
+
+/// GEM Object inner driver data
+#[pin_data]
+pub(crate) struct NovaObject {}
+
+impl gem::DriverObject for NovaObject {
+    type Driver = NovaDriver;
+    type Args = ();
+
+    fn new(_dev: &NovaDevice, _size: usize, _args: Self::Args) -> impl PinInit<Self, Error> {
+        try_pin_init!(NovaObject {})
+    }
+}
+
+impl NovaObject {
+    /// Create a new DRM GEM object.
+    pub(crate) fn new(dev: &NovaDevice, size: usize) -> Result<ARef<gem::Object<Self>>> {
+        if size == 0 {
+            return Err(EINVAL);
+        }
+        let aligned_size = page::page_align(size).ok_or(EINVAL)?;
+
+        gem::Object::<Self>::new(dev, aligned_size, ())
+    }
+
+    /// Look up a GEM object handle for a `File` and return an `ObjectRef` for it.
+    #[inline]
+    pub(crate) fn lookup_handle(
+        file: &drm::File<File>,
+        handle: u32,
+    ) -> Result<ARef<gem::Object<Self>>> {
+        gem::Object::lookup_handle(file, handle)
+    }
+}
diff --git a/drivers/gpu/drm/nova/nova.rs b/drivers/gpu/drm/nova/nova.rs
new file mode 100644
index 000000000..1fd454c7e
--- /dev/null
+++ b/drivers/gpu/drm/nova/nova.rs
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Nova DRM Driver
+
+mod driver;
+mod file;
+mod gem;
+
+use crate::driver::NovaDriver;
+
+kernel::module_auxiliary_driver! {
+    type: NovaDriver,
+    name: "nova-drm",
+    authors: ["Danilo Krummrich"],
+    description: "Nova GPU driver",
+    license: "GPL v2",
+}