[PATCH 1/2] rotate: Unregister damage across modesetting

[Michal Suchanek]

On 15 May 2012 17:03, Keith Packard <keithp at keithp.com> wrote:
> On Tue, 15 May 2012 11:41:23 +0200, Michal Suchanek <hramrach at gmail.com> wrote:
>
>> How are  you going to change screen resolution without changing the
>> pixmap?
>
> The pixmap structure gets rewritten with new contents.

Indeed, the pixmap handling is ... interesting.

However, if it is allowed to change the root->drawable  you need to
destroy the damage while the old drawable is still there.

Otherwise somebody can use the structure when the drawable and the
damage is not in sync, just as xf86CrtcRotate does.

This code is somewhat crash prone. How do all the other damage users not crash?

Or is this the only in-server use and clients are required to behave
and provide a valid drawable when dealing with damages?

Thanks

Michal