[PATCH 1/5] drm/amdgpu: Expand kernel-doc in amdgpu_ring

[Christian König]

On 16.08.25 17:31, Rodrigo Siqueira wrote:
> Expand the kernel-doc about amdgpu_ring and add some tiny improvements.
> 
> Cc: Alex Deucher <alexander.deucher at amd.com>
> Cc: Christian König <christian.koenig at amd.com>
> Cc: Timur Kristóf <timur.kristof at gmail.com>
> Signed-off-by: Rodrigo Siqueira <siqueira at igalia.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c | 15 ++++++++++++---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h |  2 ++
>  2 files changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
> index 6379bb25bf5c..78fd324c84e9 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
> @@ -75,8 +75,16 @@ unsigned int amdgpu_ring_max_ibs(enum amdgpu_ring_type type)
>   * @ring: amdgpu_ring structure holding ring information
>   * @ndw: number of dwords to allocate in the ring buffer
>   *
> - * Allocate @ndw dwords in the ring buffer (all asics).
> - * Returns 0 on success, error on failure.
> + * Allocate @ndw dwords in the ring buffer (it works in all ASICs). When
> + * inspecting the code, you may encounter places where this function is called
> + * amdgpu_ring_alloc(ring, X + Y + Z) where X, Y, and Z are integer numbers.
> + * This is a way to show how many dwords operations will be inserted in the
> + * ring. For example, if gfx_v9_0_wait_reg_mem(), amdgpu_ring_emit_reg_wait(),
> + * amdgpu_ring_emit_wreg(), and amdgpu_ring_emit_fence() will be called, before
> + * that you will see amdgpu_ring_alloc(ring, 7 + 7 + 5 + 8).

Well the rest of the patch is certainly useful, but that here made me chuckle. Isn't that obvious?

> + *
> + * Returns:
> + * 0 on success, error on failure.

We should probably adjust the return value of the function from -ENOMEM to -EINVAL when the number of the requested DW exceeds the maximum and document that here.

Apart from that looks good to me.

Christian.

>   */
>  int amdgpu_ring_alloc(struct amdgpu_ring *ring, unsigned int ndw)
>  {
> @@ -122,7 +130,8 @@ static void amdgpu_ring_alloc_reemit(struct amdgpu_ring *ring, unsigned int ndw)
>  		ring->funcs->begin_use(ring);
>  }
>  
> -/** amdgpu_ring_insert_nop - insert NOP packets
> +/**
> + * amdgpu_ring_insert_nop - insert NOP packets
>   *
>   * @ring: amdgpu_ring structure holding ring information
>   * @count: the number of NOP packets to insert
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> index 7670f5d82b9e..d27dbb3c109f 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> @@ -62,6 +62,8 @@ enum amdgpu_ring_priority_level {
>  #define AMDGPU_FENCE_FLAG_64BIT         (1 << 0)
>  #define AMDGPU_FENCE_FLAG_INT           (1 << 1)
>  #define AMDGPU_FENCE_FLAG_TC_WB_ONLY    (1 << 2)
> +
> +/* Ensure the execution in case of preemption or reset */
>  #define AMDGPU_FENCE_FLAG_EXEC          (1 << 3)
>  
>  #define to_amdgpu_ring(s) container_of((s), struct amdgpu_ring, sched)