Some questions I always wanted to ask (Glamo)

Rask Ingemann Lambertsen rask at
Wed Apr 22 02:29:48 CEST 2009

On Mon, Apr 20, 2009 at 10:58:30PM +1000, Carsten Haitzler wrote:

> the 2d unit also lacked large blobs of a 2d pipeline to
> accelerate beyond the most basic x ops (blit, fill).

   Does it not even do line drawing for the width=0 case?

[Glamo bandwidth]
> no idea. i had no idea from the paperdocs either. until much later when i
> started going "why is this so slow?" and actually did some benchmarks...

   How much is known about the bandwidth limitation? Did you benchmark more
than just plain memcpy()? For example, could you do e.g. a YUV->RGB
conversion at the same speed as plain memcpy() by spreading out the memory
accesses? Is the slowness caused by lack of memory bandwidth inside the
Glamo (e.g. because not much is left after display refresh) or it is the
external bus interface which is the bottleneck? Are any logic analyzer
traces available?

> glamo has no planned
> successor. and that made me doubt there was much value in doing full drivers as
> they have no lifespan beyond the gta02. they will never be used again anywhere -
> they will likely curl up and die in a corner of the internet :(

   But now that SMedia Tech was bought by ITE Tech, has there been any
contact with ITE Tech wrt. releasing the Glamo documentation?

Rask Ingemann Lambertsen
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