[PATCH 10/20] glamor: Add glamor_program based fill/set/get spans

[Markus Wick]

Am 2014-03-20 22:55, schrieb Keith Packard:
>> tbh, without an PBO, this is wrose than the fb fallback as it's one
>> stall per span.
> 
> Yes, it's completely miserable. However, it will never be called as the
> only paths to get here are short-circuited above this in the driver. 
> The
> only way to even test this code is to disable much of the remaining
> acceleration code.
> 
>> Also with PBO, it's still a huge overhead per span. I guess it's 
>> faster
>> for lots of spans (maybe 20+) to always fall back to fb.
>> But I don't see another non-hacky way to implement this.
> 
> And, as it won't be executed in the future, we'd best leave it as 
> simple
> as possible. Bits of the X 2D API are 'sub-optimally designed' :-)

The simplest way is to always fall back to fb. So I think we shouldn't 
implement get_spans at all but fb.