Re: [PATCH 4/6] drm/atomic: Wait for vblank whenever a plane is added to state.

From: Daniel Vetter <daniel@ffwll.ch>
To: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 4/6] drm/atomic: Wait for vblank whenever a plane is added to state.
Date: Thu, 8 Dec 2016 16:43:03 +0100	[thread overview]
Message-ID: <20161208154303.m5u2vxp4ubedb6ql@phenom.ffwll.local> (raw)
In-Reply-To: <1481204729-9058-5-git-send-email-maarten.lankhorst@linux.intel.com>

On Thu, Dec 08, 2016 at 02:45:27PM +0100, Maarten Lankhorst wrote:
> The current api doesn't take into account that whenever properties like
> rotation or z-pos change we have to wait for vblank. To make sure
> that we wait correctly, err on the side of caution and wait whenever
> a plane is added to state.

Why do we need to wait when rotation or zpos has changed? I'm a bit lost
... So rotation makes sense since often that means a special, rotated
mapping (or a different offset on omap's TILER as a different example).
But z-pos I have no idad why that matters.
-Daniel

> 
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> ---
>  drivers/gpu/drm/drm_atomic_helper.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index ccf0bed9bf4a..fdeaea84a3b7 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -1123,11 +1123,7 @@ drm_atomic_helper_wait_for_vblanks(struct drm_device *dev,
>  	for_each_crtc_in_state(old_state, crtc, old_crtc_state, i) {
>  		struct drm_crtc_state *new_crtc_state = crtc->state;
>  
> -		if (!new_crtc_state->active)
> -			continue;
> -
> -		if (!drm_atomic_helper_framebuffer_changed(dev,
> -				old_state, crtc))
> +		if (!new_crtc_state->active || !new_crtc_state->planes_changed)
>  			continue;
>  
>  		ret = drm_crtc_vblank_get(crtc);
> -- 
> 2.7.4
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx