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

[Alex Deucher]

On 9/25/07, Giuseppe Bilotta <giuseppe.bilotta at gmail.com> wrote:
> 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?

Acceleration in rotated modes requires exa composite support which is
not available in nv at the moment.

Alex