Re: [DPU PATCH 02/11] drm/msm: Don't duplicate modeset_enables atomic helper

[Sean Paul <seanpaul-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>]

On Tue, Mar 13, 2018 at 04:57:35PM -0700, Jeykumar Sankaran wrote:
> On 2018-03-12 13:21, Sean Paul wrote:
> > On Thu, Mar 08, 2018 at 04:56:01PM -0800, Jeykumar Sankaran wrote:
> > > On 2018-02-28 11:18, Sean Paul wrote:
> > > > Instead, shuffle things around so we kickoff crtc after enabling
> > encoder
> > > > during modesets. Also moves the vblank wait to after the frame.
> > > >
> > > > Change-Id: I16c7b7f9390d04f6050aa20e17a5335fbf49eba3
> > > > Signed-off-by: Sean Paul <seanpaul@chromium.org>
> > > > ---
> > > >  drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c    |   9 ++
> > > >  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c |   5 +-
> > > >  drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c     |  31 ++++-
> > > >  drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h     |   2 +
> > > >  drivers/gpu/drm/msm/msm_atomic.c            | 132
> > +-------------------
> > > >  5 files changed, 48 insertions(+), 131 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > > > index a3ab6ed2bf1d..94fab2dcca5b 100644
> > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > > > @@ -3525,6 +3525,12 @@ static void dpu_crtc_enable(struct drm_crtc
> > > > *crtc,
> > > >  	DPU_EVT32_VERBOSE(DRMID(crtc));
> > > >  	dpu_crtc = to_dpu_crtc(crtc);
> > > >
> > > > +	if (msm_is_mode_seamless(&crtc->state->adjusted_mode) ||
> > > > +	    msm_is_mode_seamless_vrr(&crtc->state->adjusted_mode)) {
> > > > +		DPU_DEBUG("Skipping crtc enable, seamless mode\n");
> > > > +		return;
> > > > +	}
> > > > +
> > > >  	pm_runtime_get_sync(crtc->dev->dev);
> > > >
> > > >  	drm_for_each_encoder(encoder, crtc->dev) {
> > > > @@ -3572,6 +3578,9 @@ static void dpu_crtc_enable(struct drm_crtc
> > *crtc,
> > > >  		DPU_POWER_EVENT_POST_ENABLE | DPU_POWER_EVENT_POST_DISABLE
> > > > |
> > > >  		DPU_POWER_EVENT_PRE_DISABLE,
> > > >  		dpu_crtc_handle_power_event, crtc, dpu_crtc->name);
> > > > +
> > > > +	if (msm_needs_vblank_pre_modeset(&crtc->state->adjusted_mode))
> > > > +		drm_crtc_wait_one_vblank(crtc);
> > > >  }
> > > >
> > > >  struct plane_state {
> > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > > > index 28ceb589ee40..4d1e3652dbf4 100644
> > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > > > @@ -3693,8 +3693,11 @@ static void
> > dpu_encoder_frame_done_timeout(struct
> > > > timer_list *t)
> > > >  static const struct drm_encoder_helper_funcs dpu_encoder_helper_funcs
> > =
> > > > {
> > > >  	.mode_set = dpu_encoder_virt_mode_set,
> > > >  	.disable = dpu_encoder_virt_disable,
> > > > -	.enable = dpu_encoder_virt_enable,
> > > > +	.enable = dpu_kms_encoder_enable,
> > > >  	.atomic_check = dpu_encoder_virt_atomic_check,
> > > > +
> > > > +	/* This is called by dpu_kms_encoder_enable */
> > > > +	.commit = dpu_encoder_virt_enable,
> > > >  };
> > > >
> > > >  static const struct drm_encoder_funcs dpu_encoder_funcs = {
> > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > > > index 81fd3a429e9f..3d83037e8305 100644
> > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > > > @@ -425,14 +425,37 @@ static void dpu_kms_prepare_commit(struct
> > msm_kms
> > > > *kms,
> > > >  			dpu_encoder_prepare_commit(encoder);
> > > >  }
> > > >
> > > > -static void dpu_kms_commit(struct msm_kms *kms,
> > > > -		struct drm_atomic_state *old_state)
> > > > +/*
> > > > + * Override the encoder enable since we need to setup the inline
> > > > rotator
> > > > and do
> > > > + * some crtc magic before enabling any bridge that might be present.
> > > > + */
> > > > +void dpu_kms_encoder_enable(struct drm_encoder *encoder)
> > > > +{
> > > > +	const struct drm_encoder_helper_funcs *funcs =
> > > > encoder->helper_private;
> > > > +	struct drm_crtc *crtc = encoder->crtc;
> > > > +
> > > > +	/* Forward this enable call to the commit hook */
> > > > +	if (funcs && funcs->commit)
> > > > +		funcs->commit(encoder);
> > > 
> > > The purpose of this function is not clear. Where are we setting up the
> > > inline rotator?
> > > Why do we need a kickoff here?
> > 
> > The reason the code is shuffled is to avoid duplicating the entire
> > atomic
> > helper
> > function. By moving calls into the ->enable hooks, we can avoid having
> > to
> > hand
> > roll the helpers.
> > 
> > The kickoff is preserved from the helper copy when you call
> > kms->funcs->commit
> > in between the encoder enable and bridge enable. If this can be removed,
> > that'd
> > be even better. I was simply trying to preserve the call order of
> > everything.
> > 
> > Sean
> I am with you on cleaning up the atomic helper copy. But using enc->commit
> helper
> to call into encoder_enable doesn't look valid to me.

"doesn't look valid to me" doesn't give me much to go on. Could you please
explain why it doesn't look valid to you?

> 
> Also, I verified removing the kms->funcs->commit call between encoder enable
> and
> bridge enable. It works fine with your newly placed kms->funcs->commit after
> drm_atomic_helper_commit_modeset_enables. So can you revisit this function?

Hmm, do you know why it was there in the first place? It seems like this was the
primary reason for copy/pasting the whole function, so it probably wasn't done
for nothing, it'd be nice to have some history on that.

Presumably you needed to remove the needs_modeset check as well?

Sean

> 
> Jeykumar S
> > 
> > > > +
> > > > +	if (crtc && crtc->state->active) {
> > > > +		DPU_EVT32(DRMID(crtc));
> > > > +		dpu_crtc_commit_kickoff(crtc);
> > > > +	}
> > > > +}
> > > > +
> > > > +static void dpu_kms_commit(struct msm_kms *kms, struct
> > drm_atomic_state
> > > > *state)
> > > >  {
> > > >  	struct drm_crtc *crtc;
> > > > -	struct drm_crtc_state *old_crtc_state;
> > > > +	struct drm_crtc_state *crtc_state;
> > > > +	struct dpu_crtc_state *cstate;
> > > >  	int i;
> > > >
> > > > -	for_each_old_crtc_in_state(old_state, crtc, old_crtc_state, i) {
> > > > +	for_each_new_crtc_in_state(state, crtc, crtc_state, i) {
> > > > +		/* If modeset is required, kickoff is run in
> > > > encoder_enable */
> > > > +		if (drm_atomic_crtc_needs_modeset(crtc_state))
> > > > +			continue;
> > > > +
> > > >  		if (crtc->state->active) {
> > > >  			DPU_EVT32(DRMID(crtc));
> > > >  			dpu_crtc_commit_kickoff(crtc);
> > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> > > > index 8cadd29a48b1..42c809ed9467 100644
> > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> > > > @@ -529,4 +529,6 @@ int dpu_kms_fbo_reference(struct dpu_kms_fbo
> > *fbo);
> > > >   */
> > > >  void dpu_kms_fbo_unreference(struct dpu_kms_fbo *fbo);
> > > >
> > > > +void dpu_kms_encoder_enable(struct drm_encoder *encoder);
> > > > +
> > > >  #endif /* __dpu_kms_H__ */
> > > > diff --git a/drivers/gpu/drm/msm/msm_atomic.c
> > > > b/drivers/gpu/drm/msm/msm_atomic.c
> > > > index 5cfb80345052..f5794dce25dd 100644
> > > > --- a/drivers/gpu/drm/msm/msm_atomic.c
> > > > +++ b/drivers/gpu/drm/msm/msm_atomic.c
> > > > @@ -84,131 +84,6 @@ static void msm_atomic_wait_for_commit_done(
> > > >  	}
> > > >  }
> > > >
> > > > -/**
> > > > - * msm_atomic_helper_commit_modeset_enables - modeset commit to
> > enable
> > > > outputs
> > > > - * @dev: DRM device
> > > > - * @old_state: atomic state object with old state structures
> > > > - *
> > > > - * This function enables all the outputs with the new configuration
> > > > which
> > > > had to
> > > > - * be turned off for the update.
> > > > - *
> > > > - * For compatibility with legacy crtc helpers this should be called
> > > > after
> > > > - * drm_atomic_helper_commit_planes(), which is what the default
> > commit
> > > > function
> > > > - * does. But drivers with different needs can group the modeset
> > commits
> > > > together
> > > > - * and do the plane commits at the end. This is useful for drivers
> > > > doing
> > > > runtime
> > > > - * PM since planes updates then only happen when the CRTC is actually
> > > > enabled.
> > > > - */
> > > > -static void msm_atomic_helper_commit_modeset_enables(struct
> > drm_device
> > > > *dev,
> > > > -		struct drm_atomic_state *old_state)
> > > > -{
> > > > -	struct drm_crtc *crtc;
> > > > -	struct drm_crtc_state *old_crtc_state;
> > > > -	struct drm_crtc_state *new_crtc_state;
> > > > -	struct drm_connector *connector;
> > > > -	struct drm_connector_state *new_conn_state;
> > > > -	struct msm_drm_private *priv = dev->dev_private;
> > > > -	struct msm_kms *kms = priv->kms;
> > > > -	int bridge_enable_count = 0;
> > > > -	int i;
> > > > -
> > > > -	for_each_oldnew_crtc_in_state(old_state, crtc, old_crtc_state,
> > > > -			new_crtc_state, i) {
> > > > -		const struct drm_crtc_helper_funcs *funcs;
> > > > -
> > > > -		/* Need to filter out CRTCs where only planes change. */
> > > > -		if (!drm_atomic_crtc_needs_modeset(new_crtc_state))
> > > > -			continue;
> > > > -
> > > > -		if (!new_crtc_state->active)
> > > > -			continue;
> > > > -
> > > > -		if (msm_is_mode_seamless(&new_crtc_state->mode) ||
> > > > -				msm_is_mode_seamless_vrr(
> > > > -				&new_crtc_state->adjusted_mode))
> > > > -			continue;
> > > > -
> > > > -		funcs = crtc->helper_private;
> > > > -
> > > > -		if (crtc->state->enable) {
> > > > -			DRM_DEBUG_ATOMIC("enabling [CRTC:%d]\n",
> > > > -					 crtc->base.id);
> > > > -
> > > > -			if (funcs->atomic_enable)
> > > > -				funcs->atomic_enable(crtc,
> > > > old_crtc_state);
> > > > -			else
> > > > -				funcs->commit(crtc);
> > > > -		}
> > > > -
> > > > -		if (msm_needs_vblank_pre_modeset(
> > > > -					&new_crtc_state->adjusted_mode))
> > > > -			drm_crtc_wait_one_vblank(crtc);
> > > > -	}
> > > > -
> > > > -	/* ensure bridge/encoder updates happen on same vblank */
> > > > -	msm_atomic_wait_for_commit_done(dev, old_state);
> > > > -
> > > > -	for_each_new_connector_in_state(old_state, connector,
> > > > -			new_conn_state, i) {
> > > > -		const struct drm_encoder_helper_funcs *funcs;
> > > > -		struct drm_encoder *encoder;
> > > > -
> > > > -		if (!new_conn_state->best_encoder)
> > > > -			continue;
> > > > -
> > > > -		if (!new_conn_state->crtc->state->active ||
> > > > -		    !drm_atomic_crtc_needs_modeset(
> > > > -			    new_conn_state->crtc->state))
> > > > -			continue;
> > > > -
> > > > -		encoder = new_conn_state->best_encoder;
> > > > -		funcs = encoder->helper_private;
> > > > -
> > > > -		DRM_DEBUG_ATOMIC("enabling [ENCODER:%d:%s]\n",
> > > > -				 encoder->base.id, encoder->name);
> > > > -
> > > > -		/*
> > > > -		 * Each encoder has at most one connector (since we always
> > > > steal
> > > > -		 * it away), so we won't call enable hooks twice.
> > > > -		 */
> > > > -		drm_bridge_pre_enable(encoder->bridge);
> > > > -		++bridge_enable_count;
> > > > -
> > > > -		if (funcs->enable)
> > > > -			funcs->enable(encoder);
> > > > -		else
> > > > -			funcs->commit(encoder);
> > > > -	}
> > > > -
> > > > -	if (kms->funcs->commit) {
> > > > -		DRM_DEBUG_ATOMIC("triggering commit\n");
> > > > -		kms->funcs->commit(kms, old_state);
> > > > -	}
> > > > -
> > > > -	/* If no bridges were pre_enabled, skip iterating over them again
> > > > */
> > > > -	if (bridge_enable_count == 0)
> > > > -		return;
> > > > -
> > > > -	for_each_new_connector_in_state(old_state, connector,
> > > > -			new_conn_state, i) {
> > > > -		struct drm_encoder *encoder;
> > > > -
> > > > -		if (!new_conn_state->best_encoder)
> > > > -			continue;
> > > > -
> > > > -		if (!new_conn_state->crtc->state->active ||
> > > > -		    !drm_atomic_crtc_needs_modeset(
> > > > -				    new_conn_state->crtc->state))
> > > > -			continue;
> > > > -
> > > > -		encoder = new_conn_state->best_encoder;
> > > > -
> > > > -		DRM_DEBUG_ATOMIC("bridge enable enabling
> > > > [ENCODER:%d:%s]\n",
> > > > -				 encoder->base.id, encoder->name);
> > > > -
> > > > -		drm_bridge_enable(encoder->bridge);
> > > > -	}
> > > > -}
> > > > -
> > > >  /* The (potentially) asynchronous part of the commit.  At this point
> > > >   * nothing can fail short of armageddon.
> > > >   */
> > > > @@ -227,7 +102,12 @@ static void complete_commit(struct msm_commit *c)
> > > >
> > > >  	drm_atomic_helper_commit_planes(dev, state, 0);
> > > >
> > > > -	msm_atomic_helper_commit_modeset_enables(dev, state);
> > > > +	drm_atomic_helper_commit_modeset_enables(dev, state);
> > > > +
> > > > +	if (kms->funcs->commit) {
> > > > +		DRM_DEBUG_ATOMIC("triggering commit\n");
> > > > +		kms->funcs->commit(kms, state);
> > > > +	}
> > > >
> > > >  	/* NOTE: _wait_for_vblanks() only waits for vblank on
> > > >  	 * enabled CRTCs.  So we end up faulting when disabling
> > > 
> > > --
> > > Jeykumar S
> 
> -- 
> Jeykumar S

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