[PATCH xserver] randr: Account for panning and transforms when constraining the cursor

[Adam Jackson]

On Mon, 2018-04-30 at 15:19 -0700, Matt Turner wrote:
> From: Chris Wilson <chris at chris-wilson.co.uk>
> 
> commit 56c90e29f04727c903bd0f084d23bf44eb1a0a11 [1.10.99.901]
> Author: Adam Jackson <ajax at redhat.com>
> Date:   Mon Nov 15 14:29:14 2010 -0500
> 
>     randr: Add RRConstrainCursorHarder
> 
> introduced a regression as it ignored the effect of panning and
> transforms upon the crtc bounds. The result was that the cursor would be
> constrained to the visible area even though the panning arena was much
> bigger, or the cursor was constrained to a region that did not even
> match the visible area when the output was transformed or reflected.

Panning was an error, but I guess that ship sailed.

> This supercedes the hack introduced by
> commit 1bf81af4a6be1113bcc3b940ab264d5c9e0f0c5d [1.12.99.904]
> Author: Rui Matos <tiagomatos at gmail.com>
> Date:   Mon Jul 30 14:32:12 2012 -0400
> 
>     xf86RandR12: Don't call ConstrainCursorHarder() if panning is enabled
> which disabled the cursor constraints if a panning mode was active, but
> did not fix the regression with arbitrary output transforms.

This patch doesn't undo randr's wrapping of CCH; should it? Seems like
it ought to...

- ajax