The hardware should not dynamically balance the load between CCS
engines. Wa_14019159160 recommends disabling it across all
platforms.
Fixes: d2eae8e98d59 ("drm/i915/dg2: Drop force_probe requirement")
Signed-off-by: Andi Shyti <andi.sh...@linux.intel.com>
Cc: Chris Wilson <chris.p.wil...@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahti...@linux.intel.com>
Cc: Matt Roper <matthew.d.ro...@intel.com>
Cc: <sta...@vger.kernel.org> # v6.2+
Reviewed-by: Matt Roper <matthew.d.ro...@intel.com>
---
drivers/gpu/drm/i915/gt/intel_gt_regs.h | 1 +
drivers/gpu/drm/i915/gt/intel_workarounds.c | 23 +++++++++++++++++++--
2 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_regs.h
b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
index 50962cfd1353..31b102604e3d 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_regs.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
@@ -1477,6 +1477,7 @@
#define ECOBITS_PPGTT_CACHE4B (0 << 8)
#define GEN12_RCU_MODE _MMIO(0x14800)
+#define XEHP_RCU_MODE_FIXED_SLICE_CCS_MODE REG_BIT(1)
#define GEN12_RCU_MODE_CCS_ENABLE REG_BIT(0)
#define CHV_FUSE_GT _MMIO(VLV_GUNIT_BASE + 0x2168)
diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c
b/drivers/gpu/drm/i915/gt/intel_workarounds.c
index b079cbbc1897..9963e5725ae5 100644
--- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
+++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
@@ -51,7 +51,8 @@
* registers belonging to BCS, VCS or VECS should be implemented in
* xcs_engine_wa_init(). Workarounds for registers not belonging to a
specific
* engine's MMIO range but that are part of of the common RCS/CCS reset
domain
- * should be implemented in general_render_compute_wa_init().
+ * should be implemented in general_render_compute_wa_init(). The settings
+ * about the CCS load balancing should be added in ccs_engine_wa_mode().
*
* - GT workarounds: the list of these WAs is applied whenever these registers
* revert to their default values: on GPU reset, suspend/resume [1]_, etc.
@@ -2854,6 +2855,22 @@ add_render_compute_tuning_settings(struct intel_gt *gt,
wa_write_clr(wal, GEN8_GARBCNTL, GEN12_BUS_HASH_CTL_BIT_EXC);
}
+static void ccs_engine_wa_mode(struct intel_engine_cs *engine, struct
i915_wa_list *wal)
+{
+ struct intel_gt *gt = engine->gt;
+
+ if (!IS_DG2(gt->i915))
+ return;
+
+ /*
+ * Wa_14019159160: This workaround, along with others, leads to
+ * significant challenges in utilizing load balancing among the
+ * CCS slices. Consequently, an architectural decision has been
+ * made to completely disable automatic CCS load balancing.
+ */
+ wa_masked_en(wal, GEN12_RCU_MODE, XEHP_RCU_MODE_FIXED_SLICE_CCS_MODE);
+}
+
/*
* The workarounds in this function apply to shared registers in
* the general render reset domain that aren't tied to a
@@ -3000,8 +3017,10 @@ engine_init_workarounds(struct intel_engine_cs *engine,
struct i915_wa_list *wal
* to a single RCS/CCS engine's workaround list since
* they're reset as part of the general render domain reset.
*/
- if (engine->flags & I915_ENGINE_FIRST_RENDER_COMPUTE)
+ if (engine->flags & I915_ENGINE_FIRST_RENDER_COMPUTE) {
general_render_compute_wa_init(engine, wal);
+ ccs_engine_wa_mode(engine, wal);
+ }
if (engine->class == COMPUTE_CLASS)
ccs_engine_wa_init(engine, wal);
--
2.43.0
