[Intel-gfx] [PATCH 08/15] drm/i915/bdw: implement semaphore signal

[Chris Wilson]

On Mon, Dec 16, 2013 at 08:50:44PM -0800, Ben Widawsky wrote:
> +static int gen8_rcs_signal(struct intel_ring_buffer *signaller,
> +			   unsigned int num_dwords)
> +{
> +#define MBOX_UPDATE_DWORDS 8
> +	struct drm_device *dev = signaller->dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct intel_ring_buffer *waiter;
> +	int i, ret, num_rings;
> +
> +	num_rings = hweight_long(INTEL_INFO(dev)->ring_mask);
> +	num_dwords = (num_rings-1) * MBOX_UPDATE_DWORDS;
> +#undef MBOX_UPDATE_DWORDS
> +
> +	/* XXX: + 4 for the caller */
> +	ret = intel_ring_begin(signaller, num_dwords + 4);
> +	if (ret)
> +		return ret;

You now pass down how many dwords the caller requires so it should just
be num_dwords += (num_rings - 1) * DWORDS_PER_MBOX; above.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre