Attachment 119376 Details for Bug 92774 – drm/i915: Request for resets under forcewake

[patch] drm/i915: Request for resets under forcewake

0001-drm-i915-Request-for-resets-under-forcewake.patch (text/plain), 1.92 KB, created by Mika Kuoppala on 2015-11-03 13:02:03 UTC

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Creator: Mika Kuoppala

Created: 2015-11-03 13:02:03 UTC

Size: 1.92 KB

patch

obsolete

>From b7cc48151febca77d3e53058aeec8f2b363bd0da Mon Sep 17 00:00:00 2001
>From: Mika Kuoppala <mika.kuoppala@intel.com>
>Date: Tue, 3 Nov 2015 12:17:00 +0200
>Subject: [PATCH] drm/i915: Request for resets under forcewake
>
>We have a timed release of a forcewake when using
>I915_READ/WRITE macros. wait_for() macro will go to
>a quite long sleep if the first read doesn't satisfy
>the condition for successful exit. With these two
>interacting, it is possible that we lose the
>forcewake during the wait_for() and the subsequent read
>will reaquire forcewake.
>
>Further experiments with skl shows that when we lose forcewake,
>we lose the reset request we submitted. So this register
>is not power context saved.
>
>Grab forcewakes for all engines before starting to request
>for resets so that all requests stay valid for the duration of
>reset requstion across all the engines.
>
>Cc: Chris Wilson <chris@chris-wilson.co.uk>
>Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
>---
> drivers/gpu/drm/i915/intel_uncore.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
>diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
>index f0f97b2..5a6e7f1b 100644
>--- a/drivers/gpu/drm/i915/intel_uncore.c
>+++ b/drivers/gpu/drm/i915/intel_uncore.c
>@@ -1483,6 +1483,8 @@ static int gen8_do_reset(struct drm_device *dev)
> 	struct intel_engine_cs *engine;
> 	int i;
> 
>+	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
>+
> 	for_each_ring(engine, dev_priv, i) {
> 		I915_WRITE(RING_RESET_CTL(engine->mmio_base),
> 			   _MASKED_BIT_ENABLE(RESET_CTL_REQUEST_RESET));
>@@ -1497,6 +1499,8 @@ static int gen8_do_reset(struct drm_device *dev)
> 		}
> 	}
> 
>+	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
>+
> 	return gen6_do_reset(dev);
> 
> not_ready:
>@@ -1504,6 +1508,8 @@ not_ready:
> 		I915_WRITE(RING_RESET_CTL(engine->mmio_base),
> 			   _MASKED_BIT_DISABLE(RESET_CTL_REQUEST_RESET));
> 
>+	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
>+
> 	return -EIO;
> }
> 
>-- 
>2.5.0
>

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Attachments on bug 92774: 119335 | 119340 | 119376

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