Re: [PATCH i-g-t] lib/intel_compute: Wait for compute walker before returning to ring

[Francois Dugast <francois.dugast@intel.com>]

On Thu, Jan 22, 2026 at 11:45:29AM +0100, Zbigniew Kempczyński wrote:
> Most compute tests don't need to synchronize at the batch level as
> kmd executes pipe-control at some point. Last xe driver proposal (link
> below) causes turning off preemption before pipe-control preventing
> entering to SIP and finish the WMTP test properly.
> 
> Change adds pipe-control at batch level causing sync wait on
> compute-walker and preventing disabling the preemption prematurely.

This looks right and does solve the issue when applying the referenced KMD
change, so it would be necessary going forward.

For maintainability, can we please replace the 8 occurrences of 0x00100000
with a define, maybe in a preparation patch?

Francois

> 
> Link: https://patchwork.freedesktop.org/series/160113/
> Signed-off-by: Zbigniew Kempczyński <zbigniew.kempczynski@intel.com>
> Cc: Matthew Brost <matthew.brost@intel.com>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
> Cc: Francois Dugast <francois.dugast@intel.com>
> ---
>  lib/intel_compute.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/lib/intel_compute.c b/lib/intel_compute.c
> index 00ef280e8f..8578b6e402 100644
> --- a/lib/intel_compute.c
> +++ b/lib/intel_compute.c
> @@ -1694,6 +1694,13 @@ static void xe2lpg_compute_exec_compute(int fd,
>  	addr_bo_buffer_batch[b++] = 0x00000000;
>  	addr_bo_buffer_batch[b++] = 0x00000000;
>  
> +	addr_bo_buffer_batch[b++] = PIPE_CONTROL;
> +	addr_bo_buffer_batch[b++] = 0x00100000;
> +	addr_bo_buffer_batch[b++] = 0x00000000;
> +	addr_bo_buffer_batch[b++] = 0x00000000;
> +	addr_bo_buffer_batch[b++] = 0x00000000;
> +	addr_bo_buffer_batch[b++] = 0x00000000;
> +
>  	addr_bo_buffer_batch[b++] = MI_BATCH_BUFFER_END;
>  }
>  
> @@ -2032,6 +2039,13 @@ static void xe3p_compute_exec_compute(int fd,
>  	addr_bo_buffer_batch[b++] = 0x00000000; /* dw62 */
>  	addr_bo_buffer_batch[b++] = 0x00000000; /* dw63 */
>  
> +	addr_bo_buffer_batch[b++] = PIPE_CONTROL;
> +	addr_bo_buffer_batch[b++] = 0x00100000;
> +	addr_bo_buffer_batch[b++] = 0x00000000;
> +	addr_bo_buffer_batch[b++] = 0x00000000;
> +	addr_bo_buffer_batch[b++] = 0x00000000;
> +	addr_bo_buffer_batch[b++] = 0x00000000;
> +
>  	addr_bo_buffer_batch[b++] = MI_BATCH_BUFFER_END;
>  }
>  
> -- 
> 2.43.0
>