On Wed, Apr 12, 2017 at 08:12:17AM +0100, Tvrtko Ursulin wrote: > > On 11/04/2017 18:58, Chris Wilson wrote: > >We indirectly hold the runtime-pm for the intel_lrc_irq_handler() by > >virtue of dev_priv->gt.awake keeping a wakeref whilst the requests are > >busy. As this is not obvious from the code, add a comment. > > > >Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > >Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > >--- > > drivers/gpu/drm/i915/intel_lrc.c | 9 +++++++++ > > 1 file changed, 9 insertions(+) > > > >diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c > >index 0dc1cc4ad6e7..e16cc28dc783 100644 > >--- a/drivers/gpu/drm/i915/intel_lrc.c > >+++ b/drivers/gpu/drm/i915/intel_lrc.c > >@@ -515,6 +515,15 @@ static void intel_lrc_irq_handler(unsigned long data) > > struct execlist_port *port = engine->execlist_port; > > struct drm_i915_private *dev_priv = engine->i915; > > > >+ /* We can skip acquiring intel_runtime_pm_get() here as it was taken > >+ * on our behalf by the request (see i915_gem_mark_busy ()) and it will > >+ * not be relinquished until the device is idle (see > >+ * i915_gem_idle_work_handler()). As a precaution, we make sure > >+ * that all ELSP are drained i.e. we have processed the CSB, > >+ * before allowing ourselves to idle and calling intel_runtime_pm_put(). > >+ */ > >+ GEM_BUG_ON(!dev_priv->gt.awake); > >+ > > intel_uncore_forcewake_get(dev_priv, engine->fw_domains); > > > > /* Prefer doing test_and_clear_bit() as a two stage operation to avoid > > > > Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > > It feels a big to c&p, but not sure if it worth putting a comment > "see comment in intel_lrc_irq_handler on why we don't have to " to > i915_guc_irq_handler or maybe dequeue? For guc, the requirement for rpm is much less strict - the interface with the guc is through ordinary memory not device memory, so we don't need rpm_get (aiui). There is the mmio readback for !llc to ensure that all GTT writes are flushed to system memory prior to dispatching the workqueue -- that technically doesn't require rpm either. I'm a bit more hesistant about adding such a comment to the guc atm, as I think I will be more misleading then helpful. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
