[PATCH] exa/mixed: avoid unnecessary dest system buffer copy in prepare_access_reg

[Michel Dänzer]

On Don, 2010-08-26 at 22:57 +1200, Karl Tomlinson wrote: 
> 
> A region is only provided to prepare_access_reg for destination pixmaps when
> the operator will not read from the destination.  A non-NULL region therefore
> indicates that no pixels in the destination gpu buffer need to be copied to
> the system buffer.
> 
> The provided region still serves a purpose, as it indicates the portion of
> the system buffer that will be damaged.
> ---
>  exa/exa_migration_mixed.c |   42 ++++++++++++++++++++++++++++--------------
>  1 files changed, 28 insertions(+), 14 deletions(-)

I like the idea of this[0], but unfortunately it breaks the transparency
of rounded window corners with compiz here, see the attached screenshot.
Are you seeing this as well?

[0] I was experimenting with always creating the damage record right
away, but I think this should provide more or less the same (and even
some more) benefits without the drawbacks.


Minor nit: Maybe region_all could only be (un)initialized when it's
actually used. Not sure it's worth bothering though.


-- 
Earthling Michel Dänzer           |                http://www.vmware.com
Libre software enthusiast         |          Debian, X and DRI developer

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