From 7c26240e8a19240924b029215989f28995f16d8c Mon Sep 17 00:00:00 2001 From: Chris Wilson 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 Cc: Mika Kuoppala Reviewed-by: Joonas Lahtinen Link: https://patchwork.freedesktop.org/patch/msgid/20171006104038.22337-1-chris@chris-wilson.co.uk Acked-by: Takashi Iwai --- 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 */