Re: [PATCH v3 1/7] drm/atomic: Add new iterators over all state, v3.

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Maarten,

Thank you for the patch.

On Monday 16 Jan 2017 10:37:38 Maarten Lankhorst wrote:
> Add for_each_(old)(new)_(plane,connector,crtc)_in_state iterators to
> replace the old for_each_xxx_in_state ones. This is useful for >1 flip
> depth and getting rid of all xxx->state dereferences.
> 
> This requires extra fixups done when committing a state after
> duplicating, which in general isn't valid but is used by suspend/resume.
> To handle these, introduce drm_atomic_helper_commit_duplicated_state
> which performs those fixups before checking & committing the state.
> 
> Changes since v1:
> - Remove nonblock parameter for commit_duplicated_state.
> Changes since v2:
> - Use commit_duplicated_state for i915 load detection.
> - Add WARN_ON(old_state != obj->state) before swapping.
> 
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> ---
>  drivers/gpu/drm/drm_atomic.c         |  6 +++
>  drivers/gpu/drm/drm_atomic_helper.c  | 65 +++++++++++++++++++++++++----
>  drivers/gpu/drm/i915/intel_display.c | 13 +++---
>  include/drm/drm_atomic.h             | 81 +++++++++++++++++++++++++++++++--
>  include/drm/drm_atomic_helper.h      |  2 +
>  5 files changed, 149 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index 6414bcf7f41b..1c1cbf436717 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -275,6 +275,8 @@ drm_atomic_get_crtc_state(struct drm_atomic_state
> *state, return ERR_PTR(-ENOMEM);
> 
>  	state->crtcs[index].state = crtc_state;
> +	state->crtcs[index].old_state = crtc->state;
> +	state->crtcs[index].new_state = crtc_state;
>  	state->crtcs[index].ptr = crtc;
>  	crtc_state->state = state;
> 
> @@ -691,6 +693,8 @@ drm_atomic_get_plane_state(struct drm_atomic_state
> *state,
> 
>  	state->planes[index].state = plane_state;
>  	state->planes[index].ptr = plane;
> +	state->planes[index].old_state = plane->state;
> +	state->planes[index].new_state = plane_state;
>  	plane_state->state = state;
> 
>  	DRM_DEBUG_ATOMIC("Added [PLANE:%d:%s] %p state to %p\n",
> @@ -1031,6 +1035,8 @@ drm_atomic_get_connector_state(struct drm_atomic_state
> *state,
> 
>  	drm_connector_reference(connector);
>  	state->connectors[index].state = connector_state;
> +	state->connectors[index].old_state = connector->state;
> +	state->connectors[index].new_state = connector_state;
>  	state->connectors[index].ptr = connector;
>  	connector_state->state = state;
> 
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c
> b/drivers/gpu/drm/drm_atomic_helper.c index b26e3419027e..d153e8a72921
> 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -1971,11 +1971,11 @@ void drm_atomic_helper_swap_state(struct
> drm_atomic_state *state, int i;
>  	long ret;
>  	struct drm_connector *connector;
> -	struct drm_connector_state *conn_state;
> +	struct drm_connector_state *conn_state, *old_conn_state;
>  	struct drm_crtc *crtc;
> -	struct drm_crtc_state *crtc_state;
> +	struct drm_crtc_state *crtc_state, *old_crtc_state;
>  	struct drm_plane *plane;
> -	struct drm_plane_state *plane_state;
> +	struct drm_plane_state *plane_state, *old_plane_state;
>  	struct drm_crtc_commit *commit;
> 
>  	if (stall) {
> @@ -1999,13 +1999,17 @@ void drm_atomic_helper_swap_state(struct
> drm_atomic_state *state, }
>  	}
> 
> -	for_each_connector_in_state(state, connector, conn_state, i) {
> +	for_each_oldnew_connector_in_state(state, connector, old_conn_state,
> conn_state, i) {
> +		WARN_ON(connector->state != old_conn_state);
> +
>  		connector->state->state = state;
>  		swap(state->connectors[i].state, connector->state);
>  		connector->state->state = NULL;
>  	}
> 
> -	for_each_crtc_in_state(state, crtc, crtc_state, i) {
> +	for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, crtc_state,
> i) {
> +		WARN_ON(crtc->state != old_crtc_state);
> +
>  		crtc->state->state = state;
>  		swap(state->crtcs[i].state, crtc->state);
>  		crtc->state->state = NULL;
> @@ -2020,7 +2024,9 @@ void drm_atomic_helper_swap_state(struct
> drm_atomic_state *state, }
>  	}
> 
> -	for_each_plane_in_state(state, plane, plane_state, i) {
> +	for_each_oldnew_plane_in_state(state, plane, old_plane_state,
> plane_state, i) {
> +		WARN_ON(plane->state != old_plane_state);
> +
>  		plane->state->state = state;
>  		swap(state->planes[i].state, plane->state);
>  		plane->state->state = NULL;
> @@ -2471,7 +2477,7 @@ EXPORT_SYMBOL(drm_atomic_helper_disable_all);
>   *
>   * See also:
>   * drm_atomic_helper_duplicate_state(), drm_atomic_helper_disable_all(),
> - * drm_atomic_helper_resume()
> + * drm_atomic_helper_resume(), drm_atomic_helper_commit_duplicated_state()
>   */
>  struct drm_atomic_state *drm_atomic_helper_suspend(struct drm_device *dev)
>  {
> @@ -2512,6 +2518,47 @@ struct drm_atomic_state
> *drm_atomic_helper_suspend(struct drm_device *dev)
> EXPORT_SYMBOL(drm_atomic_helper_suspend);
> 
>  /**
> + * drm_atomic_helper_commit_duplicated_state - commit duplicated state
> + * @state: duplicated atomic state to commit
> + * @ctx: pointer to acquire_ctx to use for commit.
> + *
> + * The state returned by drm_atomic_helper_duplicate_state() and
> + * drm_atomic_helper_suspend() is partially invalid, and needs to
> + * be fixed up before commit.

Can't you fix the state in drm_atomic_helper_suspend() to avoid the need for 
this function ?

Apart from this the patch looks good to me. I don't like the fact that we now 
have two sets of states though (state and old_state/new_state). I understand 
that you'd like to address this as part of a separate patch series, which I'm 
fine with to avoid delaying this one, but I think we should address this 
sooner rather than latter, or the API will become very confusing. Yes, that 
means mass-patching drivers I'm afraid. Could you confirm that this is your 
plan ?

> + * Returns:
> + * 0 on success or a negative error code on failure.
> + *
> + * See also:
> + * drm_atomic_helper_suspend()
> + */
> +int drm_atomic_helper_commit_duplicated_state(struct drm_atomic_state
> *state,
> +					      struct drm_modeset_acquire_ctx
> *ctx)
> +{
> +	int i;
> +	struct drm_plane *plane;
> +	struct drm_plane_state *plane_state;
> +	struct drm_connector *connector;
> +	struct drm_connector_state *conn_state;
> +	struct drm_crtc *crtc;
> +	struct drm_crtc_state *crtc_state;
> +
> +	state->acquire_ctx = ctx;
> +
> +	for_each_new_plane_in_state(state, plane, plane_state, i)
> +		state->planes[i].old_state = plane->state;
> +
> +	for_each_new_crtc_in_state(state, crtc, crtc_state, i)
> +		state->crtcs[i].old_state = crtc->state;
> +
> +	for_each_new_connector_in_state(state, connector, conn_state, i)
> +		state->connectors[i].old_state = connector->state;
> +
> +	return drm_atomic_commit(state);
> +}
> +EXPORT_SYMBOL(drm_atomic_helper_commit_duplicated_state);
> +
> +/**
>   * drm_atomic_helper_resume - subsystem-level resume helper
>   * @dev: DRM device
>   * @state: atomic state to resume to
> @@ -2534,9 +2581,9 @@ int drm_atomic_helper_resume(struct drm_device *dev,
>  	int err;
> 
>  	drm_mode_config_reset(dev);
> +
>  	drm_modeset_lock_all(dev);
> -	state->acquire_ctx = config->acquire_ctx;
> -	err = drm_atomic_commit(state);
> +	err = drm_atomic_helper_commit_duplicated_state(state,
> config->acquire_ctx);
> 	drm_modeset_unlock_all(dev);
> 
>  	return err;
> diff --git a/drivers/gpu/drm/i915/intel_display.c
> b/drivers/gpu/drm/i915/intel_display.c index f523256ef77c..74da1c380b32
> 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -3488,7 +3488,8 @@ static void intel_update_primary_planes(struct
> drm_device *dev)
> 
>  static int
>  __intel_display_resume(struct drm_device *dev,
> -		       struct drm_atomic_state *state)
> +		       struct drm_atomic_state *state,
> +		       struct drm_modeset_acquire_ctx *ctx)
>  {
>  	struct drm_crtc_state *crtc_state;
>  	struct drm_crtc *crtc;
> @@ -3512,7 +3513,7 @@ __intel_display_resume(struct drm_device *dev,
>  	/* ignore any reset values/BIOS leftovers in the WM registers */
>  	to_intel_atomic_state(state)->skip_intermediate_wm = true;
> 
> -	ret = drm_atomic_commit(state);
> +	ret = drm_atomic_helper_commit_duplicated_state(state, ctx);
> 
>  	WARN_ON(ret == -EDEADLK);
>  	return ret;
> @@ -3606,7 +3607,7 @@ void intel_finish_reset(struct drm_i915_private
> *dev_priv) */
>  			intel_update_primary_planes(dev);
>  		} else {
> -			ret = __intel_display_resume(dev, state);
> +			ret = __intel_display_resume(dev, state, ctx);
>  			if (ret)
>  				DRM_ERROR("Restoring old state failed with 
%i\n", ret);
>  		}
> @@ -3626,7 +3627,7 @@ void intel_finish_reset(struct drm_i915_private
> *dev_priv) dev_priv->display.hpd_irq_setup(dev_priv);
>  		spin_unlock_irq(&dev_priv->irq_lock);
> 
> -		ret = __intel_display_resume(dev, state);
> +		ret = __intel_display_resume(dev, state, ctx);
>  		if (ret)
>  			DRM_ERROR("Restoring old state failed with %i\n", 
ret);
> 
> @@ -11327,7 +11328,7 @@ void intel_release_load_detect_pipe(struct
> drm_connector *connector, if (!state)
>  		return;
> 
> -	ret = drm_atomic_commit(state);
> +	ret = drm_atomic_helper_commit_duplicated_state(state, ctx);
>  	if (ret)
>  		DRM_DEBUG_KMS("Couldn't release load detect pipe: %i\n", ret);
>  	drm_atomic_state_put(state);
> @@ -17210,7 +17211,7 @@ void intel_display_resume(struct drm_device *dev)
>  	}
> 
>  	if (!ret)
> -		ret = __intel_display_resume(dev, state);
> +		ret = __intel_display_resume(dev, state, &ctx);
> 
>  	drm_modeset_drop_locks(&ctx);
>  	drm_modeset_acquire_fini(&ctx);
> diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
> index f96220ed4004..6062e7f27325 100644
> --- a/include/drm/drm_atomic.h
> +++ b/include/drm/drm_atomic.h
> @@ -137,12 +137,12 @@ struct drm_crtc_commit {
> 
>  struct __drm_planes_state {
>  	struct drm_plane *ptr;
> -	struct drm_plane_state *state;
> +	struct drm_plane_state *state, *old_state, *new_state;
>  };
> 
>  struct __drm_crtcs_state {
>  	struct drm_crtc *ptr;
> -	struct drm_crtc_state *state;
> +	struct drm_crtc_state *state, *old_state, *new_state;
>  	struct drm_crtc_commit *commit;
>  	s64 __user *out_fence_ptr;
>  	unsigned last_vblank_count;
> @@ -150,7 +150,7 @@ struct __drm_crtcs_state {
> 
>  struct __drm_connnectors_state {
>  	struct drm_connector *ptr;
> -	struct drm_connector_state *state;
> +	struct drm_connector_state *state, *old_state, *new_state;
>  };
> 
>  /**
> @@ -397,6 +397,31 @@ void drm_state_dump(struct drm_device *dev, struct
> drm_printer *p); (__i)++)							
\
>  		for_each_if (connector)
> 
> +#define for_each_oldnew_connector_in_state(__state, connector,
> old_connector_state, new_connector_state, __i) \
> +	for ((__i) = 0;								
\
> +	     (__i) < (__state)->num_connector &&				
\
> +	     ((connector) = (__state)->connectors[__i].ptr,			
\
> +	     (old_connector_state) = (__state)->connectors[__i].old_state,	
\
> +	     (new_connector_state) = (__state)->connectors[__i].new_state, 1); 
	\
> +	     (__i)++)							\
> +		for_each_if (connector)
> +
> +#define for_each_old_connector_in_state(__state, connector,
> old_connector_state, __i) \ +	for ((__i) = 0;					
			\
> +	     (__i) < (__state)->num_connector &&				
\
> +	     ((connector) = (__state)->connectors[__i].ptr,			
\
> +	     (old_connector_state) = (__state)->connectors[__i].old_state, 1); 
	\
> +	     (__i)++)							\
> +		for_each_if (connector)
> +
> +#define for_each_new_connector_in_state(__state, connector,
> new_connector_state, __i) \ +	for ((__i) = 0;					
			\
> +	     (__i) < (__state)->num_connector &&				
\
> +	     ((connector) = (__state)->connectors[__i].ptr,			
\
> +	     (new_connector_state) = (__state)->connectors[__i].new_state, 1); 
	\
> +	     (__i)++)							\
> +		for_each_if (connector)
> +
>  #define for_each_crtc_in_state(__state, crtc, crtc_state, __i)	\
>  	for ((__i) = 0;						\
>  	     (__i) < (__state)->dev->mode_config.num_crtc &&	\
> @@ -405,6 +430,31 @@ void drm_state_dump(struct drm_device *dev, struct
> drm_printer *p); (__i)++)						\
>  		for_each_if (crtc_state)
> 
> +#define for_each_oldnew_crtc_in_state(__state, crtc, old_crtc_state,
> new_crtc_state, __i) \ +	for ((__i) = 0;					
		\
> +	     (__i) < (__state)->dev->mode_config.num_crtc &&		\
> +	     ((crtc) = (__state)->crtcs[__i].ptr,			\
> +	     (old_crtc_state) = (__state)->crtcs[__i].old_state,	\
> +	     (new_crtc_state) = (__state)->crtcs[__i].new_state, 1);	\
> +	     (__i)++)							\
> +		for_each_if (crtc)
> +
> +#define for_each_old_crtc_in_state(__state, crtc, old_crtc_state, __i)	
\
> +	for ((__i) = 0;							\
> +	     (__i) < (__state)->dev->mode_config.num_crtc &&		\
> +	     ((crtc) = (__state)->crtcs[__i].ptr,			\
> +	     (old_crtc_state) = (__state)->crtcs[__i].old_state, 1);	\
> +	     (__i)++)							\
> +		for_each_if (crtc)
> +
> +#define for_each_new_crtc_in_state(__state, crtc, new_crtc_state, __i)	
\
> +	for ((__i) = 0;							\
> +	     (__i) < (__state)->dev->mode_config.num_crtc &&		\
> +	     ((crtc) = (__state)->crtcs[__i].ptr,			\
> +	     (new_crtc_state) = (__state)->crtcs[__i].new_state, 1);	\
> +	     (__i)++)							\
> +		for_each_if (crtc)
> +
>  #define for_each_plane_in_state(__state, plane, plane_state, __i)		
\
>  	for ((__i) = 0;							\
>  	     (__i) < (__state)->dev->mode_config.num_total_plane &&	\
> @@ -413,6 +463,31 @@ void drm_state_dump(struct drm_device *dev, struct
> drm_printer *p); (__i)++)							
\
>  		for_each_if (plane_state)
> 
> +#define for_each_oldnew_plane_in_state(__state, plane, old_plane_state,
> new_plane_state, __i) \ +	for ((__i) = 0;					
		\
> +	     (__i) < (__state)->dev->mode_config.num_total_plane &&	\
> +	     ((plane) = (__state)->planes[__i].ptr,			\
> +	     (old_plane_state) = (__state)->planes[__i].old_state,	\
> +	     (new_plane_state) = (__state)->planes[__i].new_state, 1);	\
> +	     (__i)++)							\
> +		for_each_if (plane)
> +
> +#define for_each_old_plane_in_state(__state, plane, old_plane_state, __i) \
> +	for ((__i) = 0;							\
> +	     (__i) < (__state)->dev->mode_config.num_total_plane &&	\
> +	     ((plane) = (__state)->planes[__i].ptr,			\
> +	     (old_plane_state) = (__state)->planes[__i].old_state, 1);	\
> +	     (__i)++)							\
> +		for_each_if (plane)
> +
> +#define for_each_new_plane_in_state(__state, plane, new_plane_state, __i) \
> +	for ((__i) = 0;							\
> +	     (__i) < (__state)->dev->mode_config.num_total_plane &&	\
> +	     ((plane) = (__state)->planes[__i].ptr,			\
> +	     (new_plane_state) = (__state)->planes[__i].new_state, 1);	\
> +	     (__i)++)							\
> +		for_each_if (plane)
> +
>  /**
>   * drm_atomic_crtc_needs_modeset - compute combined modeset need
>   * @state: &drm_crtc_state for the CRTC
> diff --git a/include/drm/drm_atomic_helper.h
> b/include/drm/drm_atomic_helper.h index 9afcd3810785..2c4549e98c16 100644
> --- a/include/drm/drm_atomic_helper.h
> +++ b/include/drm/drm_atomic_helper.h
> @@ -105,6 +105,8 @@ int __drm_atomic_helper_set_config(struct drm_mode_set
> *set, int drm_atomic_helper_disable_all(struct drm_device *dev,
>  				  struct drm_modeset_acquire_ctx *ctx);
>  struct drm_atomic_state *drm_atomic_helper_suspend(struct drm_device *dev);
> +int drm_atomic_helper_commit_duplicated_state(struct drm_atomic_state
> *state,
> +					      struct drm_modeset_acquire_ctx
> *ctx);
>  int drm_atomic_helper_resume(struct drm_device *dev,
>  			     struct drm_atomic_state *state);

-- 
Regards,

Laurent Pinchart

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