[Intel-gfx] [PATCH 39/49] drm/i915/bdw: Swap the PPGTT PDPs, LRC style

[Damien Lespiau]

On Thu, Mar 27, 2014 at 06:00:08PM +0000, oscar.mateo at intel.com wrote:
> +static int gen8_write_pdp_ctx(struct i915_hw_context *ctx,
> +				   struct i915_hw_ppgtt *ppgtt)
> +{
> +	struct page *page;
> +	uint32_t *reg_state;
> +
> +	page = i915_gem_object_get_page(ctx->obj, 1);
> +	reg_state = kmap_atomic(page);
> +
> +	reg_state[CTX_PDP3_UDW+1] = ppgtt->pd_dma_addr[3] >> 32;
> +	reg_state[CTX_PDP3_LDW+1] = ppgtt->pd_dma_addr[3];
> +	reg_state[CTX_PDP2_UDW+1] = ppgtt->pd_dma_addr[2] >> 32;
> +	reg_state[CTX_PDP2_LDW+1] = ppgtt->pd_dma_addr[2];
> +	reg_state[CTX_PDP1_UDW+1] = ppgtt->pd_dma_addr[1] >> 32;
> +	reg_state[CTX_PDP1_LDW+1] = ppgtt->pd_dma_addr[1];
> +	reg_state[CTX_PDP0_UDW+1] = ppgtt->pd_dma_addr[0] >> 32;
> +	reg_state[CTX_PDP0_LDW+1] = ppgtt->pd_dma_addr[0];
> +
> +	kunmap_atomic(reg_state);
> +
> +	return 0;
> +}
> +
>  static int gen8_switch_context(struct intel_engine *ring,
>  		struct i915_hw_context *to0, u32 tail0,
>  		struct i915_hw_context *to1, u32 tail1)
>  {
> +	struct i915_hw_ppgtt *ppgtt;
> +
>  	BUG_ON(!i915_gem_obj_is_pinned(to0->obj));
>  
> -	if (to1)
> +	ppgtt = ctx_to_ppgtt(to0);
> +	gen8_write_pdp_ctx(to0, ppgtt);
> +
> +	if (to1) {
>  		BUG_ON(!i915_gem_obj_is_pinned(to1->obj));
>  
> +		ppgtt = ctx_to_ppgtt(to1);
> +		gen8_write_pdp_ctx(to1, ppgtt);
> +	}
> +

You're always calling gen8_write_pdp_ctx() and gen8_write_tail_ctx()
together, kmapping the page twice is a bit wastful.

--
Damien