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Date:   Fri, 15 Mar 2019 12:00:31 +0100
From:   Daniel Vetter <daniel@ffwll.ch>
To:     Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc:     Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        Sean Paul <sean@poorly.run>, David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Gerd Hoffmann <kraxel@redhat.com>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2] drm/atomic-helper: Make atomic_enable/disable crtc
 callbacks optional
Message-ID: <20190315110031.GY2665@phenom.ffwll.local>
Mail-Followup-To: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        Sean Paul <sean@poorly.run>, David Airlie <airlied@linux.ie>,
        Gerd Hoffmann <kraxel@redhat.com>, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
References: <20190314184845.gjmvkamobj4dilyp@smtp.gmail.com>
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On Thu, Mar 14, 2019 at 03:48:45PM -0300, Rodrigo Siqueira wrote:
> Allow atomic_enable and atomic_disable operations from
> drm_crtc_helper_funcs struct optional. With this, the target display
> drivers don't need to define a dummy function if they don't need one.
> 
> Changes since v2:
> * Don't make funcs optional
> * Update kerneldoc for atomic_enable/disable
> * Replace "if (funcs->atomic_enable)" by "if (funcs->commit)"
> * Improve commit message
> 
> Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> ---
>  drivers/gpu/drm/drm_atomic_helper.c      | 5 ++---
>  include/drm/drm_modeset_helper_vtables.h | 4 ++++
>  2 files changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index 540a77a2ade9..d506e13c2945 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -1034,7 +1034,7 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
>  			funcs->atomic_disable(crtc, old_crtc_state);
>  		else if (funcs->disable)
>  			funcs->disable(crtc);
> -		else
> +		else if (funcs->dpms)
>  			funcs->dpms(crtc, DRM_MODE_DPMS_OFF);
>  
>  		if (!(dev->irq_enabled && dev->num_crtcs))
> @@ -1277,10 +1277,9 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
>  		if (new_crtc_state->enable) {
>  			DRM_DEBUG_ATOMIC("enabling [CRTC:%d:%s]\n",
>  					 crtc->base.id, crtc->name);
> -
>  			if (funcs->atomic_enable)
>  				funcs->atomic_enable(crtc, old_crtc_state);
> -			else
> +			else if (funcs->commit)
>  				funcs->commit(crtc);
>  		}
>  	}
> diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
> index cfb7be40bed7..ce4de6b1e444 100644
> --- a/include/drm/drm_modeset_helper_vtables.h
> +++ b/include/drm/drm_modeset_helper_vtables.h
> @@ -418,6 +418,8 @@ struct drm_crtc_helper_funcs {
>  	 * Drivers can use the @old_crtc_state input parameter if the operations
>  	 * needed to enable the CRTC don't depend solely on the new state but
>  	 * also on the transition between the old state and the new state.
> +	 *
> +	 * This function is optional.
>  	 */
>  	void (*atomic_enable)(struct drm_crtc *crtc,
>  			      struct drm_crtc_state *old_crtc_state);
> @@ -441,6 +443,8 @@ struct drm_crtc_helper_funcs {
>  	 * parameter @old_crtc_state which could be used to access the old
>  	 * state. Atomic drivers should consider to use this one instead
>  	 * of @disable.
> +	 *
> +	 * This function is optional.
>  	 */
>  	void (*atomic_disable)(struct drm_crtc *crtc,
>  			       struct drm_crtc_state *old_crtc_state);
> -- 
> 2.21.0

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch