[Intel-gfx] [PATCH v6 17/20] drm/i915: Watchdog timeout: Ringbuffer command emission for gen8+

[Chris Wilson]

On Tue, Apr 18, 2017 at 01:23:32PM -0700, Michel Thierry wrote:
> @@ -1329,10 +1331,29 @@ static int gen8_emit_bb_start(struct drm_i915_gem_request *req,
>  		req->ctx->ppgtt->pd_dirty_rings &= ~intel_engine_flag(req->engine);
>  	}
>  
> -	cs = intel_ring_begin(req, 4);
> +	/* bb_start only */
> +	num_dwords = 4;
> +
> +	/* check if watchdog will be required */
> +	if (req->ctx->engine[req->engine->id].watchdog_threshold != 0) {
> +		if (!req->engine->emit_start_watchdog ||
> +		    !req->engine->emit_stop_watchdog)
> +			return -EINVAL;

This is still a bug in the context setparam to get to this point without
a watchdog.

> +
> +		/* + start_watchdog (6) + stop_watchdog (4) */
> +		num_dwords += 10;
> +		watchdog_running = true;
> +	}
> +static u32 *gen8_emit_stop_watchdog(struct drm_i915_gem_request *req, u32 *cs)
> +{
> +	struct intel_engine_cs *engine = req->engine;
> +
> +	/* XXX: no watchdog support in BCS engine */
> +	GEM_BUG_ON(engine->id == BCS);
> +
> +	*cs++ = MI_LOAD_REGISTER_IMM(2);
> +	*cs++ = i915_mmio_reg_offset(RING_CNTR(engine->mmio_base));
> +	*cs++ = get_watchdog_disable(engine);
> +	*cs++ = MI_NOOP;

Oops.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre