[Intel-gfx] [PATCH] uxa: Default to using TILING_X for pixmaps.

[Carl Worth]

On Tue, 23 Mar 2010 17:51:23 +0000, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> I believe that we have resolved all the issues since then -- as the glyph
> cache is tiled once more and nobody has been complaining about broken
> glyphs. [Except for the first few months nobody could even run 2.10 due to
> the SET_TILING brokenness...] So I think this is a relatively safe patch,
> but would appreciate a second or third opinion before merging it at this
> point.

That analysis all sounds pretty good to me.

> -		if (size < 4096)
> +		if (size <= 4096) {
>  			*tiling = I915_TILING_NONE;
> +		} else if (!IS_I965G(intel)) {
> +			/* Older hardware requires massive fences to be pot
> +			 * size aligned with a minimum of 1 MiB, so
> +			 * causes massive overallocation for small textures.
> +			 */
> +			if (size <= 1024*1024/2)
> +				*tiling = I915_TILING_NONE;
> +		}
>  	}

The nesting of these conditions seems backwards to me. Isn't the
distinction of the hardware class more significant? (In which case the
smaller 4096 limit is covered by the larger 1024*1024/2 limit anyway).

That is, I'd expect to see:

	if (!IS_I965G(intel)) {
		if (size <= 1024*1024/2)
			disable tiling;
	} else if (size < 4096) {
		disable tiling;
	}

No change in the result, of course, just something that seems to make
more sense to me at least.

-Carl
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