[PATCH] drm/amdkfd: Set SDMA_RLCx_IB_CNTL/SWITCH_INSIDE_IB

[Alex Deucher]

On Tue, Apr 22, 2025 at 4:39 PM Amber Lin <Amber.Lin at amd.com> wrote:
>
> When submitting MQD to CP, set SDMA_RLCx_IB_CNTL/SWITCH_INSIDE_IB bit so
> it'll allow SDMA preemption if there is a massive command buffer of
> long-running SDMA commands.
>
> Signed-off-by: Amber Lin <Amber.Lin at amd.com>

Acked-by: Alex Deucher <alexander.deucher at amd.com>

> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
> index 80320a6c8854..116932a20b3f 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
> @@ -495,6 +495,10 @@ static void update_mqd_sdma(struct mqd_manager *mm, void *mqd,
>         m->sdma_engine_id = q->sdma_engine_id;
>         m->sdma_queue_id = q->sdma_queue_id;
>         m->sdmax_rlcx_dummy_reg = SDMA_RLC_DUMMY_DEFAULT;
> +       /* Allow context switch so we don't cross-process starve with a massive
> +        * command buffer of long-running SDMA commands
> +        */
> +       m->sdmax_rlcx_ib_cntl |= SDMA0_GFX_IB_CNTL__SWITCH_INSIDE_IB_MASK;
>
>         q->is_active = QUEUE_IS_ACTIVE(*q);
>  }
> --
> 2.34.1
>