Re: [Intel-gfx] [PATCH] drm/i915: Do a better job at disabling primary plane in the noatomic case.

[Ander Conselvan De Oliveira <conselvan2@gmail.com>]

On Wed, 2015-11-11 at 15:36 +0100, Maarten Lankhorst wrote:
> When disable_noatomic is called plane_mask is not reliable yet,
> and plane_state->visible = true even after disabling the primary plane.

So the stale value of plane_state->visible causes a subsequent modeset to enable
the primary again?

> Fix this by unsetting plane->visible if it was visible, and calling
> disable_planes with the primary plane as mask.
> 
> The other planes are already disabled in intel_sanitize_crtc, so
> they don't have to be handled here.
> 
> Cc: stable@vger.kernel.org #v4.3, v4.2?
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92655
> Tested-by: Tomas Mezzadra <tmezzadra@gmail.com>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c
> b/drivers/gpu/drm/i915/intel_display.c
> index b5f7493213b7..bc3282ab5ed2 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -6267,9 +6267,11 @@ static void intel_crtc_disable_noatomic(struct drm_crtc
> *crtc)
>  		WARN_ON(intel_crtc->unpin_work);
>  
>  		intel_pre_disable_primary(crtc);
> +
> +		intel_crtc_disable_planes(crtc, 1 << drm_plane_index(crtc
> ->primary));
> +		to_intel_plane_state(crtc->primary->state)->visible = false;
>  	}
>  
> -	intel_crtc_disable_planes(crtc, crtc->state->plane_mask);

Can't we just make plane_mask reliable? We know whether the primary plane is
enabled and all others were disabled prior to that. Or did I miss something.

Ander

>  	dev_priv->display.crtc_disable(crtc);
>  	intel_crtc->active = false;
>  	intel_update_watermarks(crtc);