Re: [PATCH 1/6] drm/xe/migrate: Handle clear ccs logic for xe2 dgfx

[Matthew Auld <matthew.auld@intel.com>]

On 11/07/2024 10:18, Akshata Jahagirdar wrote:
> For Xe2 dGPU, we clear the bo by modifying the VRAM using an
> uncompressed pat index which then indirectly updates the
> compression status as uncompressed i.e zeroed CCS.
> So xe_migrate_clear() should be updated for BMG to not
> emit CCS surf copy commands.
> 
> Signed-off-by: Akshata Jahagirdar <akshata.jahagirdar@intel.com>
> ---
>   drivers/gpu/drm/xe/xe_device.h  | 5 +++++
>   drivers/gpu/drm/xe/xe_migrate.c | 6 +++---
>   2 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_device.h b/drivers/gpu/drm/xe/xe_device.h
> index 0a2a3e7fd402..c3093506c28c 100644
> --- a/drivers/gpu/drm/xe/xe_device.h
> +++ b/drivers/gpu/drm/xe/xe_device.h
> @@ -144,6 +144,11 @@ static inline bool xe_device_has_flat_ccs(struct xe_device *xe)
>   	return xe->info.has_flat_ccs;
>   }
>   
> +static inline bool xe_device_needs_ccs_emit(struct xe_device *xe)
> +{
> +	return xe_device_has_flat_ccs(xe) && !(GRAPHICS_VER(xe) >= 20 && IS_DGFX(xe));
> +}
> +

This should in theory be hyper specific to the migration code 
implementation. I think best keep in xe_migrate.c, instead of exporting 
(if possible).

With that,
Reviewed-by: Matthew Auld <matthew.auld@intel.com>

>   static inline bool xe_device_has_sriov(struct xe_device *xe)
>   {
>   	return xe->info.has_sriov;
> diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c
> index fa23a7e7ec43..2fc2cf375b1e 100644
> --- a/drivers/gpu/drm/xe/xe_migrate.c
> +++ b/drivers/gpu/drm/xe/xe_migrate.c
> @@ -420,7 +420,7 @@ struct xe_migrate *xe_migrate_init(struct xe_tile *tile)
>   		return ERR_PTR(err);
>   
>   	if (IS_DGFX(xe)) {
> -		if (xe_device_has_flat_ccs(xe))
> +		if (xe_device_needs_ccs_emit(xe))
>   			/* min chunk size corresponds to 4K of CCS Metadata */
>   			m->min_chunk_size = SZ_4K * SZ_64K /
>   				xe_device_ccs_bytes(xe, SZ_64K);
> @@ -1034,7 +1034,7 @@ struct dma_fence *xe_migrate_clear(struct xe_migrate *m,
>   					clear_system_ccs ? 0 : emit_clear_cmd_len(gt), 0,
>   					avail_pts);
>   
> -		if (xe_device_has_flat_ccs(xe))
> +		if (xe_device_needs_ccs_emit(xe))
>   			batch_size += EMIT_COPY_CCS_DW;
>   
>   		/* Clear commands */
> @@ -1062,7 +1062,7 @@ struct dma_fence *xe_migrate_clear(struct xe_migrate *m,
>   		if (!clear_system_ccs)
>   			emit_clear(gt, bb, clear_L0_ofs, clear_L0, XE_PAGE_SIZE, clear_vram);
>   
> -		if (xe_device_has_flat_ccs(xe)) {
> +		if (xe_device_needs_ccs_emit(xe)) {
>   			emit_copy_ccs(gt, bb, clear_L0_ofs, true,
>   				      m->cleared_mem_ofs, false, clear_L0);
>   			flush_flags = MI_FLUSH_DW_CCS;