[PATCH v7 2/3] drm/i915/gt: Do not generate the command streamer for all the CCS

[Andi Shyti]

We want a fixed load CCS balancing consisting in all slices
sharing one single user engine. For this reason do not create the
intel_engine_cs structure with its dedicated command streamer for
CCS slices beyond the first.

Fixes: d2eae8e98d59 ("drm/i915/dg2: Drop force_probe requirement")
Signed-off-by: Andi Shyti <andi.shyti at linux.intel.com>
Cc: Chris Wilson <chris.p.wilson at linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Matt Roper <matthew.d.roper at intel.com>
Cc: <stable at vger.kernel.org> # v6.2+
Acked-by: Michal Mrozek <michal.mrozek at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_engine_cs.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index f553cf4e6449..47c4a69e854c 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -908,6 +908,21 @@ static intel_engine_mask_t init_engine_mask(struct intel_gt *gt)
 		info->engine_mask &= ~BIT(GSC0);
 	}
 
+	/*
+	 * Do not create the command streamer for CCS slices beyond the first.
+	 * All the workload submitted to the first engine will be shared among
+	 * all the slices.
+	 *
+	 * Once the user will be allowed to customize the CCS mode, then this
+	 * check needs to be removed.
+	 */
+	if (IS_DG2(gt->i915)) {
+		intel_engine_mask_t first_ccs = BIT((CCS0 + __ffs(CCS_MASK(gt))));
+		intel_engine_mask_t all_ccs = CCS_MASK(gt) << CCS0;
+
+		info->engine_mask &= ~(all_ccs &= ~first_ccs);
+	}
+
 	return info->engine_mask;
 }
 
-- 
2.43.0