Commit f5d2904c authored by Andi Shyti's avatar Andi Shyti

drm/i915/gt: Disable HW load balancing for CCS

The hardware should not dynamically balance the load between CCS
engines. Wa_14019159160 recommends disabling it across all
platforms.

Fixes: d2eae8e9 ("drm/i915/dg2: Drop force_probe requirement")
Signed-off-by: default avatarAndi 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+
Reviewed-by: default avatarMatt Roper <matthew.d.roper@intel.com>
Acked-by: default avatarMichal Mrozek <michal.mrozek@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240328073409.674098-2-andi.shyti@linux.intel.com
parent fc58c693
......@@ -1478,6 +1478,7 @@
#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)
......
......@@ -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.
......@@ -2853,6 +2854,22 @@ 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
......@@ -3003,8 +3020,10 @@ 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);
......
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