[Intel-gfx] [PATCH v2 3/3] drm/i915/perf: enable OAR context save/restore of performance counters

[Chris Wilson]

Quoting Umesh Nerlige Ramappa (2019-10-17 07:11:06)
> +static int gen12_emit_oar_config(struct intel_context *ce, bool enable)
> +{
> +       struct i915_request *rq;
> +       u32 *cs;
> +       int err = 0;
> +
> +       rq = i915_request_create(ce);
> +       if (IS_ERR(rq))
> +               return PTR_ERR(rq);
> +
> +       cs = intel_ring_begin(rq, 4);
> +       if (IS_ERR(cs)) {
> +               err = PTR_ERR(cs);
> +               goto out;
> +       }
> +
> +       *cs++ = MI_LOAD_REGISTER_IMM(1);
> +       *cs++ = i915_mmio_reg_offset(RING_CONTEXT_CONTROL(ce->engine->mmio_base));
> +       *cs++ = intel_lrc_make_ctx_control(ce->engine) |

It's a masked update. It only changes the bit in the register identified
by the mask.

*cs++ = _MASKED_FIELD(GEN12_CTX_CTRL_OAR_CONTEXT_ENABLE,
		      enable ? GEN12_CTX_CTRL_OAR_CONTEXT_ENABLE : 0);


> +               (enable ?
> +                _MASKED_BIT_ENABLE(GEN12_CTX_CTRL_OAR_CONTEXT_ENABLE) :
> +                _MASKED_BIT_DISABLE(GEN12_CTX_CTRL_OAR_CONTEXT_ENABLE));
> +       *cs++ = MI_NOOP;
> +
> +       intel_ring_advance(rq, cs);
> +
> +out:
> +       i915_request_add(rq);
> +
> +       return err;
> +}

>  /*
>   * Manages updating the per-context aspects of the OA stream
>   * configuration across all contexts.
> @@ -2316,6 +2375,17 @@ static int lrc_configure_all_contexts(struct i915_perf_stream *stream,
>                         return err;
>                 }
>  
> +               /*
> +                * For Gen12, performance counters are context
> +                * saved/restored. Only enable it for the context that
> +                * requested this.
> +                */
> +               if (ctx == stream->ctx && IS_GEN(i915, 12)) {
> +                       err = gen12_configure_context_oar(ctx, oa_config != NULL);

You have the intel_context pinned already as stream->pinned_ctx.
-Chris
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