Chris Wilson <[email protected]> writes: > Quoting Chris Wilson (2017-08-21 10:28:16) >> Quoting Mika Kuoppala (2017-08-21 10:17:52) >> > Chris Wilson <[email protected]> writes: >> > >> > > During suspend we want to flush out all active contexts and their >> > > rendering. To do so we queue a request from the kernel's context, once >> > > we know that request is done, we know the GPU is completely idle. To >> > > speed up that switch bump the GPU clocks. >> > > >> > > Switching to the kernel context prior to idling is also used to enforce >> > > a barrier before changing OA properties, and when evicting active >> > > rendering from the global GTT. All cases where we do want to >> > > race-to-idle. >> > > >> > > Signed-off-by: Chris Wilson <[email protected]> >> > > Cc: David Weinehall <[email protected]> >> > > --- >> > > drivers/gpu/drm/i915/i915_gem_context.c | 11 ++++++++--- >> > > 1 file changed, 8 insertions(+), 3 deletions(-) >> > > >> > > diff --git a/drivers/gpu/drm/i915/i915_gem_context.c >> > > b/drivers/gpu/drm/i915/i915_gem_context.c >> > > index 58a2a44f88bd..ca1423ad2708 100644 >> > > --- a/drivers/gpu/drm/i915/i915_gem_context.c >> > > +++ b/drivers/gpu/drm/i915/i915_gem_context.c >> > > @@ -895,6 +895,7 @@ int i915_gem_switch_to_kernel_context(struct >> > > drm_i915_private *dev_priv) >> > > >> > > for_each_engine(engine, dev_priv, id) { >> > > struct drm_i915_gem_request *req; >> > > + bool active = false; >> > > int ret; >> > > >> > > if (engine_has_kernel_context(engine)) >> > > @@ -913,13 +914,17 @@ int i915_gem_switch_to_kernel_context(struct >> > > drm_i915_private *dev_priv) >> > > prev = i915_gem_active_raw(&tl->last_request, >> > > >> > > &dev_priv->drm.struct_mutex); >> > > if (prev) >> > > - >> > > i915_sw_fence_await_sw_fence_gfp(&req->submit, >> > > - >> > > &prev->submit, >> > > - >> > > GFP_KERNEL); >> > > + active |= >> > > i915_sw_fence_await_sw_fence_gfp(&req->submit, >> > > + >> > > &prev->submit, >> > > + >> > > GFP_KERNEL) > 0; >> > >> > There is no point of kicking the clocks if we are the only request left? >> > >> > Well logical as the request is empty, just pondering if the actual ctx >> > save/restore would finish quicker. >> >> I was thinking if it was just the context save itself, it not would be >> enough of a difference to justify itself. Just gut feeling and not >> measured, I worry about the irony of boosting from idle just to idle. > > Hmm, or we could be more precise and just set the clocks high rather > than queue a task. The complication isn't worth it for just a single > callsite, but I am contemplating supplying boost/clocks information > along with the request.
For the purposes of suspend, I think the approach is simple and good enough. Can David give a Tested-by? Reviewed-by: Mika Kuoppala <[email protected]> > -Chris _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
