On kbl evidence indicates that even if the hardware happily
tells us to proceed with reset, it really isn't ready.
Resetting a freely running batchbuffer after we have ack for readiness,
still can cause a system hang.
We also have similar experiences on older gens. So now
attempt to stop engines before proceeding for reset, on all
gens where we have a gpu reset. This has shown to improve reset
reliability and reduce the risk of losing the machine.
v2: Add fixme for wa (Joonas)
Testcase: igt/prime_busy/hang-* # kbl
Cc: Joonas Lahtinen <joonas.lahti...@linux.intel.com>
Cc: Chris Wilson <ch...@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
Signed-off-by: Mika Kuoppala <mika.kuopp...@intel.com>
Acked-by: Chris Wilson <ch...@chris-wilson.co.uk>
Acked-by: Joonas Lahtinen <joonas.lahti...@linux.intel.com>
---
drivers/gpu/drm/i915/intel_uncore.c | 75 +++++++++++++++++++++----------------
1 file changed, 43 insertions(+), 32 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_uncore.c
b/drivers/gpu/drm/i915/intel_uncore.c
index 97525de2cee4..fdd7f93acb4f 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -1354,33 +1354,39 @@ int i915_reg_read_ioctl(struct drm_device *dev,
return ret;
}
-static void gen3_stop_rings(struct drm_i915_private *dev_priv)
+static void gen3_stop_engine(struct intel_engine_cs *engine)
+{
+ struct drm_i915_private *dev_priv = engine->i915;
+ const u32 base = engine->mmio_base;
+ const i915_reg_t mode = RING_MI_MODE(base);
+
+ I915_WRITE_FW(mode, _MASKED_BIT_ENABLE(STOP_RING));
+ if (intel_wait_for_register_fw(dev_priv,
+ mode,
+ MODE_IDLE,
+ MODE_IDLE,
+ 500))
+ DRM_DEBUG_DRIVER("%s: timed out on STOP_RING\n",
+ engine->name);
+
+ I915_WRITE_FW(RING_CTL(base), 0);
+ I915_WRITE_FW(RING_HEAD(base), 0);
+ I915_WRITE_FW(RING_TAIL(base), 0);
+
+ /* Check acts as a post */
+ if (I915_READ_FW(RING_HEAD(base)) != 0)
+ DRM_DEBUG_DRIVER("%s: ring head not parked\n",
+ engine->name);
+}
+
+static void i915_stop_engines(struct drm_i915_private *dev_priv,
+ unsigned engine_mask)
{
struct intel_engine_cs *engine;
enum intel_engine_id id;
- for_each_engine(engine, dev_priv, id) {
- const u32 base = engine->mmio_base;
- const i915_reg_t mode = RING_MI_MODE(base);
-
- I915_WRITE_FW(mode, _MASKED_BIT_ENABLE(STOP_RING));
- if (intel_wait_for_register_fw(dev_priv,
- mode,
- MODE_IDLE,
- MODE_IDLE,
- 500))
- DRM_DEBUG_DRIVER("%s: timed out on STOP_RING\n",
- engine->name);
-
- I915_WRITE_FW(RING_CTL(base), 0);
- I915_WRITE_FW(RING_HEAD(base), 0);
- I915_WRITE_FW(RING_TAIL(base), 0);
-
- /* Check acts as a post */
- if (I915_READ_FW(RING_HEAD(base)) != 0)
- DRM_DEBUG_DRIVER("%s: ring head not parked\n",
- engine->name);
- }
+ for_each_engine_masked(engine, dev_priv, engine_mask, id)
+ gen3_stop_engine(engine);
}
static bool i915_reset_complete(struct pci_dev *pdev)
@@ -1415,9 +1421,6 @@ static int g33_do_reset(struct drm_i915_private
*dev_priv, unsigned engine_mask)
{
struct pci_dev *pdev = dev_priv->drm.pdev;
- /* Stop engines before we reset; see g4x_do_reset() below for why. */
- gen3_stop_rings(dev_priv);
-
pci_write_config_byte(pdev, I915_GDRST, GRDOM_RESET_ENABLE);
return wait_for(g4x_reset_complete(pdev), 500);
}
@@ -1432,12 +1435,6 @@ static int g4x_do_reset(struct drm_i915_private
*dev_priv, unsigned engine_mask)
I915_READ(VDECCLK_GATE_D) | VCP_UNIT_CLOCK_GATE_DISABLE);
POSTING_READ(VDECCLK_GATE_D);
- /* We stop engines, otherwise we might get failed reset and a
- * dead gpu (on elk).
- * WaMediaResetMainRingCleanup:ctg,elk (presumably)
- */
- gen3_stop_rings(dev_priv);
-
pci_write_config_byte(pdev, I915_GDRST,
GRDOM_MEDIA | GRDOM_RESET_ENABLE);
ret = wait_for(g4x_reset_complete(pdev), 500);
@@ -1742,6 +1739,20 @@ int intel_gpu_reset(struct drm_i915_private *dev_priv,
unsigned engine_mask)
*/
intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
for (retry = 0; retry < 3; retry++) {
+
+ /* We stop engines, otherwise we might get failed reset and a
+ * dead gpu (on elk). Also as modern gpu as kbl can suffer
+ * from system hang if batchbuffer is progressing when
+ * the reset is issued, regardless of READY_TO_RESET ack.
+ * Thus assume it is best to stop engines on all gens
+ * where we have a gpu reset.
+ *
+ * WaMediaResetMainRingCleanup:ctg,elk (presumably)
+ *
+ * FIXME: Wa for more modern gens needs to be validated
+ */
+ i915_stop_engines(dev_priv, engine_mask);
+
ret = reset(dev_priv, engine_mask);
if (ret != -ETIMEDOUT)
break;
--
2.11.0
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