From mboxrd@z Thu Jan  1 00:00:00 1970
From: Chris Wilson <chris@chris-wilson.co.uk>
Subject: Re: [PATCH 1/2] drm/i915: enable semaphores on
	per-device defaults
Date: Mon, 21 Nov 2011 13:33:40 +0000
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Cc: Daniel Vetter <daniel.vetter@ffwll.ch>, Ben Widawsky <ben@bwidawsk.net>, Eugeni Dodonov <eugeni.dodonov@intel.com>
List-Id: intel-gfx@lists.freedesktop.org

On Mon, 21 Nov 2011 11:22:09 -0200, Eugeni Dodonov <eugeni.dodonov@intel.com> wrote:
> We should enable semaphores on IVB by default, and on SNB in cases where
> dma remapping is disabled or iommu is not enabled.
> 
> v2: adapt patch according to the feedback, and put it in line with Keith's
> rc6 enabling patch.
> 
> v3: move the generation check into intel_enable_semaphores function, and
> fix variable type for i915_semaphores.
> 
> CC: Daniel Vetter <daniel.vetter@ffwll.ch>
> CC: Ben Widawsky <ben@bwidawsk.net>
> CC: Keith Packard <keithp@keithp.com>
> CC: Jesse Barnes <jbarnes@virtuousgeek.org>
> CC: Chris Wilson <chris@chris-wilson.co.uk>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=42696
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=40564
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=41353
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=38862
> Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
>  
> +static bool
> +intel_enable_semaphores(struct drm_device *dev)
> +{
> +	if (INTEL_INFO(dev)->gen < 6)
> +		return 0;
> +
> +	if (i915_semaphores >= 0)
> +		return i915_semaphores;
> +
> +	if (INTEL_INFO(dev)->gen >= 7)
> +		return 1;
> +#ifdef CONFIG_INTEL_IOMMU
> +	/* On gen6, we only enable semaphores if dma remapping is disabled,
> +	 * or if there is no iommu.
> +	 */
> +	if (INTEL_INFO(dev)->gen == 6)
> +		return no_iommu || dmar_disabled;
> +#endif
> +
> +	return 1;
> +}

Now this function can be written more compactly by just removing the
gen >= 7 check. Otherwise,
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre