Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes:
> After a reset, we will ensure that there is at least one request
> submitted to HW to ensure that a context is loaded for powersaving.
> Let's wait for this submission via a tasklet to complete before we drop
> our forcewake, ensuring the system is ready for rc6 before we let it
> possible sleep.
s/possible/possibly ?
>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_gem.h | 6 ++++++
> drivers/gpu/drm/i915/intel_lrc.c | 15 ++++++++++++++-
> 2 files changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h
> index 62ee4e385365..261da577829a 100644
> --- a/drivers/gpu/drm/i915/i915_gem.h
> +++ b/drivers/gpu/drm/i915/i915_gem.h
> @@ -82,4 +82,10 @@ static inline void __tasklet_disable_sync_once(struct tasklet_struct *t)
> tasklet_unlock_wait(t);
> }
>
> +static inline void __tasklet_enable_sync_once(struct tasklet_struct *t)
> +{
> + if (atomic_dec_return(&t->count) == 0)
> + tasklet_kill(t);
> +}
> +
> #endif /* __I915_GEM_H__ */
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index b3a5cfb7689f..f2fb48b1a7b7 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -1877,6 +1877,8 @@ execlists_reset_prepare(struct intel_engine_cs *engine)
>
> GEM_TRACE("%s\n", engine->name);
>
> + intel_uncore_forcewake_get(engine->i915, FORCEWAKE_ALL);
> +
> /*
> * Prevent request submission to the hardware until we have
> * completed the reset in i915_gem_reset_finish(). If a request
> @@ -2007,7 +2009,18 @@ static void execlists_reset(struct intel_engine_cs *engine,
>
> static void execlists_reset_finish(struct intel_engine_cs *engine)
> {
> - tasklet_enable(&engine->execlists.tasklet);
> + /*
> + * Flush the tasklet while we still have the forcewake to be sure
> + * that it is not allowed to sleep before we restart and reload a
> + * context.
> + *
> + * As before (with execlists_reset_prepare) we rely on the caller
> + * serialising mutiple attempts to reset so that we know that we
s/mutiple/multiple
> + * are the only one manipulating tasklet state.
> + */
> + __tasklet_enable_sync_once(&engine->execlists.tasklet);
> +
> + intel_uncore_forcewake_put(engine->i915, FORCEWAKE_ALL);
as discussed in irc, we already hold forcewakes on behalf of
prepare_engine() above us.
With forcewake_put/get removed,
Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
>
> GEM_TRACE("%s\n", engine->name);
> }
> --
> 2.17.0
>
> _______________________________________________
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