Hardware cannot be in a middle of idle flow messaging
when we pull the plug from ringbuffer. Disable idle
messaging before we do so to avoid potential deadlock
on engine initialization and reset.
v2: INVALID_MMIO_REG, unconditional enable (Chris)
v3: comment (Chris), bspec reference
References: bspec/11751
Cc: Chris Wilson <ch...@chris-wilson.co.uk>
Acked-by: Chris Wilson <ch...@chris-wilson.co.uk>
Signed-off-by: Mika Kuoppala <mika.kuopp...@linux.intel.com>
---
drivers/gpu/drm/i915/intel_engine_cs.c | 64 +++++++++++++++++++++++++-
1 file changed, 63 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c
b/drivers/gpu/drm/i915/intel_engine_cs.c
index 2a94b92cfcd3..10cb6b22fe92 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -764,7 +764,7 @@ int intel_engine_init_common(struct intel_engine_cs *engine)
/**
* intel_engines_cleanup_common - cleans up the engine state created by
- * the common initiailizers.
+ * the common initializers.
* @engine: Engine to cleanup.
*
* This cleans up everything created by the common helpers.
@@ -865,6 +865,63 @@ void intel_engine_cancel_stop_cs(struct intel_engine_cs
*engine)
_MASKED_BIT_DISABLE(STOP_RING));
}
+static i915_reg_t get_idle_poll_reg(const struct intel_engine_cs *engine)
+{
+ if (engine->id != RCS)
+ return INVALID_MMIO_REG;
+
+ if (IS_GEN(engine->i915, 9))
+ return GEN9_RCS_FE_FSM2;
+
+ if (IS_GEN(engine->i915, 8))
+ return GEN6_RCS_PWR_FSM;
+
+ return INVALID_MMIO_REG;
+}
+
+static void disable_idle_messaging(struct intel_engine_cs *engine)
+{
+ struct drm_i915_private *dev_priv = engine->i915;
+ i915_reg_t poll_reg;
+
+ poll_reg = get_idle_poll_reg(engine);
+ if (!i915_mmio_reg_valid(poll_reg))
+ return;
+
+ GEM_DEBUG_WARN_ON(I915_READ_FW(GEN6_RC_SLEEP_PSMI_CONTROL) &
+ GEN6_PSMI_SLEEP_MSG_DISABLE);
+ /*
+ * Hardware must not be in middle of idle flow signalling
+ * when the RING_CTL is zeroed. In order to prevent this
+ * we disable the messaging temporarily.
+ */
+ I915_WRITE_FW(GEN6_RC_SLEEP_PSMI_CONTROL,
+ _MASKED_BIT_ENABLE(GEN6_PSMI_SLEEP_MSG_DISABLE));
+
+ /*
+ * Poll the magic bits to ensure that engine state machine
+ * is in valid state for stopping the ring.
+ */
+ if (__intel_wait_for_register_fw(dev_priv, poll_reg,
+ 0x7f, 0x30,
+ 5000, 0,
+ NULL))
+ DRM_DEBUG_DRIVER("psmi idle msg poll timeout\n");
+}
+
+static void enable_idle_messaging(struct intel_engine_cs *engine)
+{
+ struct drm_i915_private *dev_priv = engine->i915;
+ i915_reg_t poll_reg;
+
+ poll_reg = get_idle_poll_reg(engine);
+ if (!i915_mmio_reg_valid(poll_reg))
+ return;
+
+ I915_WRITE_FW(GEN6_RC_SLEEP_PSMI_CONTROL,
+ _MASKED_BIT_DISABLE(GEN6_PSMI_SLEEP_MSG_DISABLE));
+}
+
int intel_engine_stop_ring(struct intel_engine_cs *engine)
{
struct drm_i915_private *dev_priv = engine->i915;
@@ -880,9 +937,14 @@ int intel_engine_stop_ring(struct intel_engine_cs *engine)
I915_WRITE_FW(RING_TAIL(base), 0);
POSTING_READ_FW(RING_TAIL(base));
+ /* Idle messaging needs to be off during ring disable */
+ disable_idle_messaging(engine);
+
/* The ring must be empty before it is disabled */
I915_WRITE_FW(RING_CTL(base), 0);
+ enable_idle_messaging(engine);
+
/* Check acts as a post */
if (I915_READ_FW(RING_HEAD(base))) {
GEM_TRACE("%s: ring head [%x] not parked\n",
--
2.17.1
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