Merge tag 'amd-drm-next-6.16-2025-05-09' of https://gitlab.freedesktop.org/agd5f/linux into drm-next

amd-drm-next-6.16-2025-05-09:

amdgpu:
- IPS fixes
- DSC cleanup
- DC Scaling updates
- DC FP fixes
- Fused I2C-over-AUX updates
- SubVP fixes
- Freesync fix
- DMUB AUX fixes
- VCN fix
- Hibernation fixes
- HDP fixes
- DCN 2.1 fixes
- DPIA fixes
- DMUB updates
- Use drm_file_err in amdgpu
- Enforce isolation updates
- Use new dma_fence helpers
- USERQ fixes
- Documentation updates
- Misc code cleanups
- SR-IOV updates
- RAS updates
- PSP 12 cleanups

amdkfd:
- Update error messages for SDMA
- Userptr updates

drm:
- Add drm_file_err function

dma-buf:
- Add a helper to sort and deduplicate dma_fence arrays

From: Alex Deucher <alexander.deucher@amd.com>
Link: https://lore.kernel.org/r/20250509230951.3871914-1-alexander.deucher@amd.com
Signed-off-by: Dave Airlie <airlied@redhat.com>

2 files changed, 90 insertions, 0 deletions

diff --git a/Documentation/gpu/amdgpu/gc/index.rst b/Documentation/gpu/amdgpu/gc/index.rst
new file mode 100644
index 000000000000..ff6e9ef5cbee
--- /dev/null
+++ b/Documentation/gpu/amdgpu/gc/index.rst
@@ -0,0 +1,52 @@
+.. _amdgpu-gc:
+
+========================================
+ drm/amdgpu - Graphics and Compute (GC)
+========================================
+
+The relationship between the CPU and GPU can be described as the
+producer-consumer problem, where the CPU fills out a buffer with operations
+(producer) to be executed by the GPU (consumer). The requested operations in
+the buffer are called Command Packets, which can be summarized as a compressed
+way of transmitting command information to the graphics controller.
+
+The component that acts as the front end between the CPU and the GPU is called
+the Command Processor (CP). This component is responsible for providing greater
+flexibility to the GC since CP makes it possible to program various aspects of
+the GPU pipeline. CP also coordinates the communication between the CPU and GPU
+via a mechanism named **Ring Buffers**, where the CPU appends information to
+the buffer while the GPU removes operations. It is relevant to highlight that a
+CPU can add a pointer to the Ring Buffer that points to another region of
+memory outside the Ring Buffer, and CP can handle it; this mechanism is called
+**Indirect Buffer (IB)**. CP receives and parses the Command Streams (CS), and
+writes the operations to the correct hardware blocks.
+
+Graphics (GFX) and Compute Microcontrollers
+-------------------------------------------
+
+GC is a large block, and as a result, it has multiple firmware associated with
+it. Some of them are:
+
+CP (Command Processor)
+    The name for the hardware block that encompasses the front end of the
+    GFX/Compute pipeline. Consists mainly of a bunch of microcontrollers
+    (PFP, ME, CE, MEC). The firmware that runs on these microcontrollers
+    provides the driver interface to interact with the GFX/Compute engine.
+
+    MEC (MicroEngine Compute)
+        This is the microcontroller that controls the compute queues on the
+        GFX/compute engine.
+
+    MES (MicroEngine Scheduler)
+        This is the engine for managing queues. For more details check
+        :ref:`MicroEngine Scheduler (MES) <amdgpu-mes>`.
+
+RLC (RunList Controller)
+    This is another microcontroller in the GFX/Compute engine. It handles
+    power management related functionality within the GFX/Compute engine.
+    The name is a vestige of old hardware where it was originally added
+    and doesn't really have much relation to what the engine does now.
+
+.. toctree::
+
+   mes.rst
diff --git a/Documentation/gpu/amdgpu/gc/mes.rst b/Documentation/gpu/amdgpu/gc/mes.rst
new file mode 100644
index 000000000000..b99eb211b179
--- /dev/null
+++ b/Documentation/gpu/amdgpu/gc/mes.rst
@@ -0,0 +1,38 @@
+.. _amdgpu-mes:
+
+=============================
+ MicroEngine Scheduler (MES)
+=============================
+
+.. note::
+   Queue and ring buffer are used as a synonymous.
+
+.. note::
+   This section assumes that you are familiar with the concept of Pipes, Queues, and GC.
+   If not, check :ref:`GFX, Compute, and SDMA Overall Behavior<pipes-and-queues-description>`
+   and :ref:`drm/amdgpu - Graphics and Compute (GC) <amdgpu-gc>`.
+
+Every GFX has a pipe component with one or more hardware queues. Pipes can
+switch between queues depending on certain conditions, and one of the
+components that can request a queue switch to a pipe is the MicroEngine
+Scheduler (MES). Whenever the driver is initialized, it creates one MQD per
+hardware queue, and then the MQDs are handed to the MES firmware for mapping
+to:
+
+1. Kernel Queues (legacy): This queue is statically mapped to HQDs and never
+   preempted. Even though this is a legacy feature, it is the current default, and
+   most existing hardware supports it. When an application submits work to the
+   kernel driver, it submits all of the application command buffers to the kernel
+   queues. The CS IOCTL takes the command buffer from the applications and
+   schedules them on the kernel queue.
+
+2. User Queues: These queues are dynamically mapped to the HQDs. Regarding the
+   utilization of User Queues, the userspace application will create its user
+   queues and submit work directly to its user queues with no need to IOCTL for
+   each submission and no need to share a single kernel queue.
+
+In terms of User Queues, MES can dynamically map them to the HQD. If there are
+more MQDs than HQDs, the MES firmware will preempt other user queues to make
+sure each queues get a time slice; in other words, MES is a microcontroller
+that handles the mapping and unmapping of MQDs into HQDs, as well as the
+priorities and oversubscription of MQDs.