From 7c26240e8a19240924b029215989f28995f16d8c Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Fri, 6 Oct 2017 11:40:38 +0100
Subject: [PATCH] drm/i915: Try harder to finish the idle-worker
Git-commit: 7c26240e8a19240924b029215989f28995f16d8c
Patch-mainline: v4.15-rc1
References: FATE#322643 bsc#1055900
If a worker requeues itself, it may switch to a different kworker pool,
which flush_work() considers as complete. To be strict, we then need to
keep flushing the work until it is no longer pending.
References: https://bugs.freedesktop.org/show_bug.cgi?id=102456
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171006104038.22337-1-chris@chris-wilson.co.uk
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpu/drm/i915/i915_debugfs.c | 3 +--
drivers/gpu/drm/i915/i915_gem.c | 3 +--
drivers/gpu/drm/i915/i915_utils.h | 13 +++++++++++++
3 files changed, 15 insertions(+), 4 deletions(-)
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -4258,8 +4258,7 @@ fault_irq_set(struct drm_i915_private *i
mutex_unlock(&i915->drm.struct_mutex);
/* Flush idle worker to disarm irq */
- while (flush_delayed_work(&i915->gt.idle_work))
- ;
+ drain_delayed_work(&i915->gt.idle_work);
return 0;
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4557,8 +4557,7 @@ int i915_gem_suspend(struct drm_i915_pri
/* As the idle_work is rearming if it detects a race, play safe and
* repeat the flush until it is definitely idle.
*/
- while (flush_delayed_work(&dev_priv->gt.idle_work))
- ;
+ drain_delayed_work(&dev_priv->gt.idle_work);
/* Assert that we sucessfully flushed all the work and
* reset the GPU back to its idle, low power state.
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -124,4 +124,17 @@ static inline void __list_del_many(struc
WRITE_ONCE(head->next, first);
}
+/*
+ * Wait until the work is finally complete, even if it tries to postpone
+ * by requeueing itself. Note, that if the worker never cancels itself,
+ * we will spin forever.
+ */
+static inline void drain_delayed_work(struct delayed_work *dw)
+{
+ do {
+ while (flush_delayed_work(dw))
+ ;
+ } while (delayed_work_pending(dw));
+}
+
#endif /* !__I915_UTILS_H */