Quoting Tomasz Lis (2018-10-15 20:29:18) > The patch adds support of preempt-to-idle requesting by setting a proper > bit within Execlist Control Register, and receiving preemption result from > Context Status Buffer. > > Preemption in previous gens required a special batch buffer to be executed, > so the Command Streamer never preempted to idle directly. In Icelake it is > possible, as there is a hardware mechanism to inform the kernel about > status of the preemption request. > > This patch does not cover using the new preemption mechanism when GuC is > active. > > v2: Added needs_preempt_context() change so that it is not created when > preempt-to-idle is supported. (Chris) > Updated setting HWACK flag so that it is cleared after > preempt-to-dle. (Chris, Daniele) > Updated to use I915_ENGINE_HAS_PREEMPTION flag. (Chris) > > v3: Fixed needs_preempt_context() change. (Chris) > Merged preemption trigger functions to one. (Chris) > Fixed conyext state tonot assume COMPLETED_MASK after preemption, > since idle-to-idle case will not have it set. > > v4: Simplified needs_preempt_context() change. (Daniele) > Removed clearing HWACK flag in idle-to-idle preempt. (Daniele) > > v5: Renamed inject_preempt_context(). (Daniele) > Removed duplicated GEM_BUG_ON() on HWACK (Daniele) > > Bspec: 18922 > Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> > Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx> > Cc: Michal Winiarski <michal.winiarski@xxxxxxxxx> > Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxx> > Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx> This R-b was on v4, and should be indicated with # v4 comment. The commit message doesn't say much about why preempting to idle is beneficial? The pre-Gen11 codepath needs to be maintained anyway. Regards, Joonas _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
