Quoting Tvrtko Ursulin (2018-09-14 10:40:43) > > On 14/09/2018 09:34, Chris Wilson wrote: > > Once we have flushed the first request through the system to both load a > > context and record the default state; tell the GPU to park and idle > > itself, putting itself immediately (hopefully at least) into a > > powersaving state, and allowing ourselves to start from known state > > after setting up all our bookkeeping. > > Otherwise this would happen after a second or so, when the idle work > handler does it. Crucial thing to mention is I think the park/unpark > cycle which sets up the pinned default state. Hmm, I didn't think it was worth highlight it here as one assumes that all the bookkeeping is equally required :) I pulled out for special mention in the comment, because I thought that was relevant to the function where we are acquiring the default_state. > Alternative to patch could be to extract > __intel_engine_pin_default_state to be called from here and from > intel_engines_unpark. > > But I guess there is some value in going powersave as soon as possible > so okay. Yeah. Later on (as in patches that have been on the ml for several months with feature requests depending on them...) we acquire a load_powersaving_context() function, which should make this a little more interesting. > > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > > Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > > --- > > drivers/gpu/drm/i915/i915_gem.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c > > index 89834ce19acd..be9d012d851b 100644 > > --- a/drivers/gpu/drm/i915/i915_gem.c > > +++ b/drivers/gpu/drm/i915/i915_gem.c > > @@ -5414,6 +5414,14 @@ static int __intel_engines_record_defaults(struct drm_i915_private *i915) > > > > assert_kernel_context_is_current(i915); > > > > + /* > > + * Immediately park the GPU so that we enable powersaving and > > + * treat it as idle. The next time we issue a request, we will > > + * unpark and start using the engine->pinned_default_state, otherwise > > + * it is in limbo and an early reset may fail. > > + */ > > + __i915_gem_park(i915); > > Why not after we have grabbed the default state? I was just wanting to tie it to the switch to kernel-context + idle. I was thinking this was the closed point to the normal park sequence. > I was worried this might access a sleeping device but apparently at > least vma unbind takes the rpm ref. Still, just this I think makes it > more logical to park after we have grabbed the default state, instead o > putting the device to sleep and then immediately waking up below. Oh, we have wakerefs aplenty on module load, we are not assuming gt.awake here. -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
