Re: [PATCH v4 01/11] drm: Add atomic variants of enable/disable to encoder helper funcs

[Sean Paul <sean@poorly.run>]

On Wed, May 08, 2019 at 06:31:24PM +0200, Daniel Vetter wrote:
> On Wed, May 08, 2019 at 12:09:06PM -0400, Sean Paul wrote:
> > From: Sean Paul <seanpaul@chromium.org>
> > 
> > This patch adds atomic_enable and atomic_disable callbacks to the
> > encoder helpers. This will allow encoders to make informed decisions in
> > their start-up/shutdown based on the committed state.
> > 
> > Aside from the new hooks, this patch also introduces the new signature
> > for .atomic_* functions going forward. Instead of passing object state
> > (well, encoders don't have atomic state, but let's ignore that), we pass
> > the entire atomic state so the driver can inspect more than what's
> > happening locally.
> > 
> > This is particularly important for the upcoming self refresh helpers.
> > 
> > Changes in v3:
> > - Added patch to the set
> > Changes in v4:
> > - Move atomic_disable above prepare (Daniel)
> > - Add breadcrumb to .enable() docbook (Daniel)
> 
> Why no r-b: me or did you not apply all my suggestions? Too lazy to read
> it all again :-)

Sorry, I was being a bit conservative slapping your R-b on the patches I
changed. I've incorporated all of your suggestions AFAICT, so I've applied R-b
on patches 01/03/04/05 (conveniently the same patch numbers between v3 & v4).
Unless there's other review feedback I'll probably not send those out. I will
send out an update to Laurent's patch with your suggestions and R-b after a bit
of soak time on the list.

Sean


> -Daniel
> 
> > 
> > Link to v3: https://patchwork.freedesktop.org/patch/msgid/20190502194956.218441-2-sean@poorly.run
> > 
> > Cc: Daniel Vetter <daniel@ffwll.ch>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Signed-off-by: Sean Paul <seanpaul@chromium.org>
> > ---
> >  drivers/gpu/drm/drm_atomic_helper.c      |  8 +++-
> >  include/drm/drm_modeset_helper_vtables.h | 48 ++++++++++++++++++++++++
> >  2 files changed, 54 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> > index 553415fe8ede..ccf01831f265 100644
> > --- a/drivers/gpu/drm/drm_atomic_helper.c
> > +++ b/drivers/gpu/drm/drm_atomic_helper.c
> > @@ -999,7 +999,9 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
> >  
> >  		/* Right function depends upon target state. */
> >  		if (funcs) {
> > -			if (new_conn_state->crtc && funcs->prepare)
> > +			if (funcs->atomic_disable)
> > +				funcs->atomic_disable(encoder, old_state);
> > +			else if (new_conn_state->crtc && funcs->prepare)
> >  				funcs->prepare(encoder);
> >  			else if (funcs->disable)
> >  				funcs->disable(encoder);
> > @@ -1309,7 +1311,9 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
> >  		drm_bridge_pre_enable(encoder->bridge);
> >  
> >  		if (funcs) {
> > -			if (funcs->enable)
> > +			if (funcs->atomic_enable)
> > +				funcs->atomic_enable(encoder, old_state);
> > +			else if (funcs->enable)
> >  				funcs->enable(encoder);
> >  			else if (funcs->commit)
> >  				funcs->commit(encoder);
> > diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
> > index 8f3602811eb5..aa509c107083 100644
> > --- a/include/drm/drm_modeset_helper_vtables.h
> > +++ b/include/drm/drm_modeset_helper_vtables.h
> > @@ -675,6 +675,51 @@ struct drm_encoder_helper_funcs {
> >  	enum drm_connector_status (*detect)(struct drm_encoder *encoder,
> >  					    struct drm_connector *connector);
> >  
> > +	/**
> > +	 * @atomic_disable:
> > +	 *
> > +	 * This callback should be used to disable the encoder. With the atomic
> > +	 * drivers it is called before this encoder's CRTC has been shut off
> > +	 * using their own &drm_crtc_helper_funcs.atomic_disable hook. If that
> > +	 * sequence is too simple drivers can just add their own driver private
> > +	 * encoder hooks and call them from CRTC's callback by looping over all
> > +	 * encoders connected to it using for_each_encoder_on_crtc().
> > +	 *
> > +	 * This callback is a variant of @disable that provides the atomic state
> > +	 * to the driver. It takes priority over @disable during atomic commits.
> > +	 *
> > +	 * This hook is used only by atomic helpers. Atomic drivers don't need
> > +	 * to implement it if there's no need to disable anything at the encoder
> > +	 * level. To ensure that runtime PM handling (using either DPMS or the
> > +	 * new "ACTIVE" property) works @atomic_disable must be the inverse of
> > +	 * @atomic_enable.
> > +	 */
> > +	void (*atomic_disable)(struct drm_encoder *encoder,
> > +			       struct drm_atomic_state *state);
> > +
> > +	/**
> > +	 * @atomic_enable:
> > +	 *
> > +	 * This callback should be used to enable the encoder. It is called
> > +	 * after this encoder's CRTC has been enabled using their own
> > +	 * &drm_crtc_helper_funcs.atomic_enable hook. If that sequence is
> > +	 * too simple drivers can just add their own driver private encoder
> > +	 * hooks and call them from CRTC's callback by looping over all encoders
> > +	 * connected to it using for_each_encoder_on_crtc().
> > +	 *
> > +	 * This callback is a variant of @enable that provides the atomic state
> > +	 * to the driver. It is called in place of @enable during atomic
> > +	 * commits.
> > +	 *
> > +	 * This hook is used only by atomic helpers, for symmetry with @disable.
> > +	 * Atomic drivers don't need to implement it if there's no need to
> > +	 * enable anything at the encoder level. To ensure that runtime PM
> > +	 * handling (using either DPMS or the new "ACTIVE" property) works
> > +	 * @enable must be the inverse of @disable for atomic drivers.
> > +	 */
> > +	void (*atomic_enable)(struct drm_encoder *encoder,
> > +			      struct drm_atomic_state *state);
> > +
> >  	/**
> >  	 * @disable:
> >  	 *
> > @@ -691,6 +736,9 @@ struct drm_encoder_helper_funcs {
> >  	 * handling (using either DPMS or the new "ACTIVE" property) works
> >  	 * @disable must be the inverse of @enable for atomic drivers.
> >  	 *
> > +	 * For atomic drivers also consider @atomic_disable and save yourself
> > +	 * from having to read the NOTE below!
> > +	 *
> >  	 * NOTE:
> >  	 *
> >  	 * With legacy CRTC helpers there's a big semantic difference between
> > -- 
> > Sean Paul, Software Engineer, Google / Chromium OS
> > 
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

-- 
Sean Paul, Software Engineer, Google / Chromium OS