drm/i915/gt: Do not generate the command streamer for all the CCS

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@linux.intel.com>
Cc: Chris Wilson <chris.p.wilson@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: <stable@vger.kernel.org> # v6.2+
Acked-by: Michal Mrozek <michal.mrozek@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240328073409.674098-3-andi.shyti@linux.intel.com

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index f553cf4e644904cc7c3eee45dfa48726b9215ed7..7e98940d89bdc9a936bfa5c9ed1a924f2a90d674 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -908,6 +908,23 @@ 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)) {
+               u8 first_ccs = __ffs(CCS_MASK(gt));
+
+               /* Mask off all the CCS engine */
+               info->engine_mask &= ~GENMASK(CCS3, CCS0);
+               /* Put back in the first CCS engine */
+               info->engine_mask |= BIT(_CCS(first_ccs));
+       }
+
        return info->engine_mask;
 }