drm/xe: Ensure fixed_slice_mode gets set after ccs_mode change

The RCU_MODE_FIXED_SLICE_CCS_MODE setting is not getting invoked
in the gt reset path after the ccs_mode setting by the user.
Add it to engine register update list (in hw_engine_setup_default_state())
which ensures it gets set in the gt reset and engine reset paths.

v2: Add register update to engine list to ensure it gets updated
after engine reset also.

Fixes: 0d97ecc ("drm/xe: Enable Fixed CCS mode setting")
Cc: stable@vger.kernel.org
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20250327185604.18230-1-niranjana.vishwanathapura@intel.com

drivers/gpu/drm/xe/xe_hw_engine.c

@@ -389,12 +389,6 @@ xe_hw_engine_setup_default_lrc_state(struct xe_hw_engine *hwe)
 				 blit_cctl_val,
 				 XE_RTP_ACTION_FLAG(ENGINE_BASE)))
 		},
-		/* Use Fixed slice CCS mode */
-		{ XE_RTP_NAME("RCU_MODE_FIXED_SLICE_CCS_MODE"),
-		  XE_RTP_RULES(FUNC(xe_hw_engine_match_fixed_cslice_mode)),
-		  XE_RTP_ACTIONS(FIELD_SET(RCU_MODE, RCU_MODE_FIXED_SLICE_CCS_MODE,
-					   RCU_MODE_FIXED_SLICE_CCS_MODE))
-		},
 		/* Disable WMTP if HW doesn't support it */
 		{ XE_RTP_NAME("DISABLE_WMTP_ON_UNSUPPORTED_HW"),
 		  XE_RTP_RULES(FUNC(xe_rtp_cfeg_wmtp_disabled)),
@@ -461,6 +455,12 @@ hw_engine_setup_default_state(struct xe_hw_engine *hwe)
 		  XE_RTP_ACTIONS(SET(CSFE_CHICKEN1(0), CS_PRIORITY_MEM_READ,
 				     XE_RTP_ACTION_FLAG(ENGINE_BASE)))
 		},
+		/* Use Fixed slice CCS mode */
+		{ XE_RTP_NAME("RCU_MODE_FIXED_SLICE_CCS_MODE"),
+		  XE_RTP_RULES(FUNC(xe_hw_engine_match_fixed_cslice_mode)),
+		  XE_RTP_ACTIONS(FIELD_SET(RCU_MODE, RCU_MODE_FIXED_SLICE_CCS_MODE,
+					   RCU_MODE_FIXED_SLICE_CCS_MODE))
+		},
 	};
 
 	xe_rtp_process_to_sr(&ctx, engine_entries, ARRAY_SIZE(engine_entries), &hwe->reg_sr);