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SubjectRe: __i915_spin_request() sucks
Previous patch was obvious pre-coffee crap, this should work for using
ktime to spin max 1usec.

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 5cf4a1998273..21192e55c33c 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1148,17 +1148,18 @@ static bool missed_irq(struct drm_i915_private *dev_priv,

static int __i915_spin_request(struct drm_i915_gem_request *req)
{
- unsigned long timeout;
+ ktime_t timeout;

if (i915_gem_request_get_ring(req)->irq_refcount)
return -EBUSY;

- timeout = jiffies + 1;
+ timeout = ktime_get();
+ ktime_add_us(timeout, 1);
while (!need_resched()) {
if (i915_gem_request_completed(req, true))
return 0;

- if (time_after_eq(jiffies, timeout))
+ if (ktime_after(ktime_get(), timeout))
break;

cpu_relax_lowlatency();
--
Jens Axboe



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