Re: [PATCH] drm/i915: Make sure fb objects with rotated views are also fenceable

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

Hi,

On 09/12/2015 02:44 AM, Vivek Kasireddy wrote:
> From: Vivek Kasireddy <vivek.kasireddy@intel.com>
>
> Currently, fb objects with rotated views are ignored while pinning. Therefore,
> include the rotated view type and use the view size instead of the object's
> size to determine if it is fenceable. And, look at the view and its offset
> while writing and pinning to the fence registers.

I didn't figure out from the commit message if something is broken or?

AFAIR rotated views deliberately skip on fencing since rotated view has 
shuffled pages in memory so it would be a weird view for userspace to 
handle.

Especially this below:

>   static void i965_write_fence_reg(struct drm_device *dev, int reg,
> -				 struct drm_i915_gem_object *obj)
> +				 struct drm_i915_gem_object *obj,
> +				 const struct i915_ggtt_view *view)
>   {
>   	struct drm_i915_private *dev_priv = dev->dev_private;
>   	int fence_reg;
>   	int fence_pitch_shift;
> +	const struct i915_ggtt_view *ggtt_view = view;
>
>   	if (INTEL_INFO(dev)->gen >= 6) {
>   		fence_reg = FENCE_REG_SANDYBRIDGE_0;
> @@ -95,9 +97,13 @@ static void i965_write_fence_reg(struct drm_device *dev, int reg,
>   			size = (size / row_size) * row_size;
>   		}
>
> -		val = (uint64_t)((i915_gem_obj_ggtt_offset(obj) + size - 4096) &
> -				 0xfffff000) << 32;
> -		val |= i915_gem_obj_ggtt_offset(obj) & 0xfffff000;
> +		if (!ggtt_view)
> +			ggtt_view = &i915_ggtt_view_normal;
> +
> +		val = (uint64_t)((i915_gem_obj_ggtt_offset_view((obj), ggtt_view)
> +				  + size - 4096) & 0xfffff000) << 32;
> +		val |= i915_gem_obj_ggtt_offset_view((obj), ggtt_view) & 0xfffff000;
> +

Looks like the code can be setting up a fence with a rotated view GGTT 
address which looks wrong? Is this really what is wanted and why?

Regards,

Tvrtko
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