From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 7 Feb 2018 15:13:50 +0000
Subject: drm/i915: Mark the device as wedged from the beginning of set-wedged
Git-commit: 0d73e7a095f768fad5a002bf6732c675e2aee44b
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166
Reduce the window of opportunity for set-wedged being called
concurrently with reset (after i915_reset() has performed the
i915_gem_unset_wedged()) by moving the set_bit(I915_WEDGED) to before we
complete the inflight requests. When i915_reset() is being blocked on a
request, such completion may allow it to start and beginning resetting
the GPU before i915_gem_set_wedged() has finished (and so before
set-wedge will have marked the device as wedged). As such,
i915_gem_init_hw() may see a wedged device even from inside
i915_reset().
References: 36703e79a982 ("drm/i915: Break modeset deadlocks on reset")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180207151350.20883-1-chris@chris-wilson.co.uk
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
drivers/gpu/drm/i915/i915_gem.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3213,6 +3213,9 @@ void i915_gem_set_wedged(struct drm_i915
intel_engine_dump(engine, &p, "%s\n", engine->name);
}
+ set_bit(I915_WEDGED, &i915->gpu_error.flags);
+ smp_mb__after_atomic();
+
/*
* First, stop submission to hw, but do not yet complete requests by
* rolling the global seqno forward (since this would complete requests
@@ -3254,7 +3257,8 @@ void i915_gem_set_wedged(struct drm_i915
for_each_engine(engine, i915, id) {
unsigned long flags;
- /* Mark all pending requests as complete so that any concurrent
+ /*
+ * Mark all pending requests as complete so that any concurrent
* (lockless) lookup doesn't try and wait upon the request as we
* reset it.
*/
@@ -3266,7 +3270,6 @@ void i915_gem_set_wedged(struct drm_i915
i915_gem_reset_finish_engine(engine);
}
- set_bit(I915_WEDGED, &i915->gpu_error.flags);
wake_up_all(&i915->gpu_error.reset_queue);
}