[PATCH v5] drm/tidss: dispc: Fix broken plane positioning code

[Tomi Valkeinen]

On 24/02/2020 22:02, Jyri Sarha wrote:
> The old implementation of placing planes on the CRTC while configuring
> the planes was naive and relied on the order in which the planes were
> configured, enabled, and disabled. The situation where a plane's zpos
> was changed on the fly was completely broken. The usual symptoms of
> this problem was scrambled display and a flood of sync lost errors,
> when a plane was active in two layers at the same time, or a missing
> plane, in case when a layer was accidentally disabled.
> 
> The rewrite takes a more straight forward approach when HW is
> concerned. The plane positioning registers are in the CRTC (or
> actually OVR) register space and it is more natural to configure them
> in a one go when configuring the CRTC. To do this we need make sure we
> have all the planes on the updated CRTCs in the new atomic state. The
> untouched planes on CRTCs that need plane position update are added to
> the atomic state in tidss_atomic_check().
> 
> Signed-off-by: Jyri Sarha <jsarha at ti.com>

Reviewed-by: Tomi Valkeinen <tomi.valkeinen at ti.com>

  Tomi

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