[Intel-gfx] [PATCH v5 3/5] drm/i915: Watchdog timeout: Ringbuffer command emission for gen8+

[Chris Wilson]

Quoting Carlos Santa (2019-03-22 23:41:16)
>  static int gen8_emit_bb_start(struct i915_request *rq,
>                               u64 offset, u32 len,
>                               const unsigned int flags)
>  {
> +       struct intel_engine_cs *engine = rq->engine;
> +       struct i915_gem_context *ctx = rq->gem_context;
> +       struct intel_context *ce = intel_context_lookup(ctx, engine);
>         u32 *cs;
> +       u32 num_dwords;
> +       bool enable_watchdog = false;
>  
> -       cs = intel_ring_begin(rq, 6);
> +       /* bb_start only */
> +       num_dwords = 6;
> +
> +       /* check if watchdog will be required */
> +       if (ce->watchdog_threshold != 0) {
> +               /* + start_watchdog (6) + stop_watchdog (4) */
> +               num_dwords += 10;
> +               enable_watchdog = true;

What do you do about the recommendation not to enable the watchdog
across semaphores inside user batches? Is that caveat made clear in the
uAPI docs?
-Chris