From: Tilak Tangudu <tilak.tang...@intel.com> Prior to doing a reset, SW must ensure command streamer is stopped, as a workaround, to eliminate a race condition in GPM flow. Setting both the ring stop and prefetch disable bits, will cause the command streamer to halt.
v2: 1. Removed duplicate code and added only prefetch disable -Chris Wilson v3: 1. Applied wa for all gen12+ -Lahtinen Joonas/Vivi Rodrigo v4: 1. Added description in comment 2. Added WA prior to read barrier-Chris Wilson v5: 1. Modified to disable prefetch and wait for idle ack -Chris Wilson Signed-off-by: Tilak Tangudu <tilak.tang...@intel.com> --- drivers/gpu/drm/i915/gt/intel_engine_cs.c | 9 +++++++++ drivers/gpu/drm/i915/gt/intel_engine_regs.h | 1 + 2 files changed, 10 insertions(+) diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c index 98b61ff13c95..14c6ddbbfde8 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c @@ -1280,6 +1280,15 @@ static int __intel_engine_stop_cs(struct intel_engine_cs *engine, int err; intel_uncore_write_fw(uncore, mode, _MASKED_BIT_ENABLE(STOP_RING)); + + /* + * Wa_22011802037 : gen12, Prior to doing a reset, ensure CS is + * stopped, set ring stop bit and prefetch disable bit to halt CS + */ + if (GRAPHICS_VER(engine->i915) == 12) + intel_uncore_write_fw(uncore, RING_MODE_GEN7(engine->mmio_base), + _MASKED_BIT_ENABLE(GEN12_GFX_PREFETCH_DISABLE)); + err = __intel_wait_for_register_fw(engine->uncore, mode, MODE_IDLE, MODE_IDLE, fast_timeout_us, diff --git a/drivers/gpu/drm/i915/gt/intel_engine_regs.h b/drivers/gpu/drm/i915/gt/intel_engine_regs.h index 0bf8b45c9319..594a629cb28f 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_regs.h +++ b/drivers/gpu/drm/i915/gt/intel_engine_regs.h @@ -181,6 +181,7 @@ #define GFX_SURFACE_FAULT_ENABLE (1 << 12) #define GFX_REPLAY_MODE (1 << 11) #define GFX_PSMI_GRANULARITY (1 << 10) +#define GEN12_GFX_PREFETCH_DISABLE REG_BIT(10) #define GFX_PPGTT_ENABLE (1 << 9) #define GEN8_GFX_PPGTT_48B (1 << 7) #define GFX_FORWARD_VBLANK_MASK (3 << 5) -- 2.35.1