If at first we don't succeed, try again.
Running the reset and recovery routines in a loop ends in a "reset
request timeout" with a mtbf of an hour on Braswell. This is eerily
similar to the unrecoverable reset condition that first prompted us to
use the reset-request mechanism in commit 7fd2d26921d1 ("drm/i915: Reset
request handling for gen8+"). Repeating the reset request makes the
failure much harder to reproduce (but there is no reason to believe that
it is more than mere paper over a timing or other issue).
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
Cc: Arun Siluvery <arun.siluvery@xxxxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
drivers/gpu/drm/i915/intel_uncore.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index e9f68cd56e32..1be8ced03ba5 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -1688,20 +1688,22 @@ int intel_wait_for_register(struct drm_i915_private *dev_priv,
static int gen8_request_engine_reset(struct intel_engine_cs *engine)
{
struct drm_i915_private *dev_priv = engine->i915;
- int ret;
+ int loop = 3;
- I915_WRITE_FW(RING_RESET_CTL(engine->mmio_base),
- _MASKED_BIT_ENABLE(RESET_CTL_REQUEST_RESET));
+ do {
+ I915_WRITE_FW(RING_RESET_CTL(engine->mmio_base),
+ _MASKED_BIT_ENABLE(RESET_CTL_REQUEST_RESET));
- ret = intel_wait_for_register_fw(dev_priv,
- RING_RESET_CTL(engine->mmio_base),
- RESET_CTL_READY_TO_RESET,
- RESET_CTL_READY_TO_RESET,
- 700);
- if (ret)
- DRM_ERROR("%s: reset request timeout\n", engine->name);
+ if (!intel_wait_for_register_fw(dev_priv,
+ RING_RESET_CTL(engine->mmio_base),
+ RESET_CTL_READY_TO_RESET,
+ RESET_CTL_READY_TO_RESET,
+ 700))
+ return 0;
+ } while (--loop);
- return ret;
+ DRM_ERROR("%s: reset request timeout\n", engine->name);
+ return -EIO;
}
static void gen8_unrequest_engine_reset(struct intel_engine_cs *engine)
--
2.9.3
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