Hi!
Reported-by: Jens Axboe axboe@kernel.dk Link: https://lkml.org/lkml/2015/11/12/621 Cc: Jens Axboe axboe@kernel.dk Cc; "Rogozhkin, Dmitry V" dmitry.v.rogozhkin@intel.com Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Tvrtko Ursulin tvrtko.ursulin@linux.intel.com Cc: Eero Tamminen eero.t.tamminen@intel.com Cc: "Rantala, Valtteri" valtteri.rantala@intel.com Cc: stable@kernel.vger.org
drivers/gpu/drm/i915/i915_gem.c | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 740530c571d1..2a88158bd1f7 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1146,14 +1146,36 @@ static bool missed_irq(struct drm_i915_private *dev_priv, return test_bit(ring->id, &dev_priv->gpu_error.missed_irq_rings); }
+static u64 local_clock_us(unsigned *cpu) +{
- u64 t;
- *cpu = get_cpu();
- t = local_clock() >> 10;
- put_cpu();
- return t;
+}
+static bool busywait_stop(u64 timeout, unsigned cpu) +{
- unsigned this_cpu;
- if (time_after64(local_clock_us(&this_cpu), timeout))
return true;- return this_cpu != cpu;
+}
Perhaps you want to ask the timekeeping people for the right primitive? I guess you are not the only one needing this.. Pavel