Quoting Chris Wilson (2017-10-23 22:32:35) > When we park the engine (upon idling), we kill the irq tasklet. However, > to be sure that it is not restarted by a final interrupt after doing so, > flush the interrupt handler before parking. As we only park the engines > when we believe the system is idle, there should not be any spurious > interrupts later to distrub us; so flushing the final in-flight > interrupt should be sufficient. > > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> > Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx> > Cc: Imre Deak <imre.deak@xxxxxxxxx> > --- > drivers/gpu/drm/i915/i915_gem.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c > index bb0e85043e01..b547a6327d34 100644 > --- a/drivers/gpu/drm/i915/i915_gem.c > +++ b/drivers/gpu/drm/i915/i915_gem.c > @@ -3327,6 +3327,12 @@ i915_gem_idle_work_handler(struct work_struct *work) > if (new_requests_since_last_retire(dev_priv)) > goto out_unlock; > > + /* > + * Be paranoid and flush a concurrent interrupt to make sure > + * we don't reactivate any irq tasklets after parking. * FIXME: Note that even though we have waited for execlists to be idle, * there may still be an in-flight interrupt even though the CSB * is now empty. synchronize_irq() makes sure that the residual * interrupt is completed before we continue, but it doesn't prevent * the HW from raising that residual interrupt later. To complete * the shield we should coordinate disabling the CS irq with * flushing the residual interrupt. > + */ > + synchronize_irq(dev_priv->drm.irq); > + > /* > * We are committed now to parking the engines, make sure there > * will be no more interrupts arriving later. > -- > 2.15.0.rc1 > _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
