nv 2.1.x: why no acceleration with RandR rotation enabled and screen not rotated?

[Giuseppe Bilotta]

Hello all,

I just dist-upgraded my Debian unstable and got the new X.org,
including nv 2.1.3. Browsing the man page I found out that it
was possible to enable RandR rotation with an appropriate option.
As documented in the man page, enabling this disables acceleration
(and this is indeed quite perceptible).

So I was wondering if there are technical reasons for the
acceleration to be disabled by just enabling the option, even
when the screen is not actually rotated. I don't know the
implementation details, but I would imagine it to be possible to
select the accelerated path when the screen isn't rotated, and
only fall back to unaccelerated when the screen actually gets
rotated. Or is it just not possible with the current RnR and
acceleration? Is there something I can read on the matter?

-- 
Giuseppe "Oblomov" Bilotta