[Intel-gfx] [PATCH v2 6/6] drm/i915: Add a cursor hack to allow converting legacy page flip to atomic, v3.

[Archit Taneja]

Hi,

On 12/12/2016 4:04 PM, Maarten Lankhorst wrote:
> Do something similar to vc4, only allow updating the cursor state
> in-place through a fastpath when the watermarks are unaffected. This
> will allow cursor movement to be smooth, but changing cursor size or
> showing/hiding cursor will still fall back so watermarks can be updated.
>
> Only moving and changing fb is allowed.

I was implementing something similar for msm kms. I have a comment/query
below.

>
> Changes since v1:
> - Set page flip to always_unused for trybot.
> - Copy fence correctly, ignore plane_state->state, should be NULL.
> - Check crtc_state for !active and modeset, go to slowpath if the case.
> Changes since v2:
> - Make error handling work correctly. (Matthew Auld)
>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_atomic_plane.c |  47 +++++++----
>  drivers/gpu/drm/i915/intel_display.c      | 132 +++++++++++++++++++++++++++++-
>  drivers/gpu/drm/i915/intel_drv.h          |   2 +
>  3 files changed, 163 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_atomic_plane.c b/drivers/gpu/drm/i915/intel_atomic_plane.c
> index dbe9fb41ae53..60d75ce8a989 100644
> --- a/drivers/gpu/drm/i915/intel_atomic_plane.c
> +++ b/drivers/gpu/drm/i915/intel_atomic_plane.c
> @@ -103,36 +103,24 @@ intel_plane_destroy_state(struct drm_plane *plane,
>  	drm_atomic_helper_plane_destroy_state(plane, state);
>  }
>
> -static int intel_plane_atomic_check(struct drm_plane *plane,
> -				    struct drm_plane_state *state)
> +int intel_plane_atomic_check_with_state(struct intel_crtc_state *crtc_state,
> +					struct intel_plane_state *intel_state)
>  {
> +	struct drm_plane *plane = intel_state->base.plane;
>  	struct drm_i915_private *dev_priv = to_i915(plane->dev);
> -	struct drm_crtc *crtc = state->crtc;
> -	struct intel_crtc *intel_crtc;
> -	struct intel_crtc_state *crtc_state;
> +	struct drm_plane_state *state = &intel_state->base;
>  	struct intel_plane *intel_plane = to_intel_plane(plane);
> -	struct intel_plane_state *intel_state = to_intel_plane_state(state);
> -	struct drm_crtc_state *drm_crtc_state;
>  	int ret;
>
> -	crtc = crtc ? crtc : plane->state->crtc;
> -	intel_crtc = to_intel_crtc(crtc);
> -
>  	/*
>  	 * Both crtc and plane->crtc could be NULL if we're updating a
>  	 * property while the plane is disabled.  We don't actually have
>  	 * anything driver-specific we need to test in that case, so
>  	 * just return success.
>  	 */
> -	if (!crtc)
> +	if (!intel_state->base.crtc && !plane->state->crtc)
>  		return 0;
>
> -	drm_crtc_state = drm_atomic_get_existing_crtc_state(state->state, crtc);
> -	if (WARN_ON(!drm_crtc_state))
> -		return -EINVAL;
> -
> -	crtc_state = to_intel_crtc_state(drm_crtc_state);
> -
>  	/* Clip all planes to CRTC size, or 0x0 if CRTC is disabled */
>  	intel_state->clip.x1 = 0;
>  	intel_state->clip.y1 = 0;
> @@ -184,6 +172,31 @@ static int intel_plane_atomic_check(struct drm_plane *plane,
>  	return intel_plane_atomic_calc_changes(&crtc_state->base, state);
>  }
>
> +static int intel_plane_atomic_check(struct drm_plane *plane,
> +				    struct drm_plane_state *state)
> +{
> +	struct drm_crtc *crtc = state->crtc;
> +	struct drm_crtc_state *drm_crtc_state;
> +
> +	crtc = crtc ? crtc : plane->state->crtc;
> +
> +	/*
> +	 * Both crtc and plane->crtc could be NULL if we're updating a
> +	 * property while the plane is disabled.  We don't actually have
> +	 * anything driver-specific we need to test in that case, so
> +	 * just return success.
> +	 */
> +	if (!crtc)
> +		return 0;
> +
> +	drm_crtc_state = drm_atomic_get_existing_crtc_state(state->state, crtc);
> +	if (WARN_ON(!drm_crtc_state))
> +		return -EINVAL;
> +
> +	return intel_plane_atomic_check_with_state(to_intel_crtc_state(drm_crtc_state),
> +						   to_intel_plane_state(state));
> +}
> +
>  static void intel_plane_atomic_update(struct drm_plane *plane,
>  				      struct drm_plane_state *old_state)
>  {
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 9eaf1e5bdae9..5568ecac2edc 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -15028,6 +15028,136 @@ const struct drm_plane_funcs intel_plane_funcs = {
>  	.atomic_destroy_state = intel_plane_destroy_state,
>  };
>
> +static int
> +intel_legacy_cursor_update(struct drm_plane *plane,
> +			   struct drm_crtc *crtc,
> +			   struct drm_framebuffer *fb,
> +			   int crtc_x, int crtc_y,
> +			   unsigned int crtc_w, unsigned int crtc_h,
> +			   uint32_t src_x, uint32_t src_y,
> +			   uint32_t src_w, uint32_t src_h)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(crtc->dev);
> +	int ret;
> +	struct drm_plane_state *old_plane_state, *new_plane_state;
> +	struct intel_plane *intel_plane = to_intel_plane(plane);
> +	struct drm_framebuffer *old_fb;
> +	struct drm_crtc_state *crtc_state = crtc->state;
> +
> +	/*
> +	 * When crtc is inactive or there is a modeset pending,
> +	 * wait for it to complete in the slowpath
> +	 */
> +	if (!crtc_state->active || needs_modeset(crtc_state) ||
> +	    to_intel_crtc_state(crtc_state)->update_pipe)
> +		goto slow;
> +
> +	old_plane_state = plane->state;
> +
> +	/*
> +	 * If any parameters change that may affect watermarks,
> +	 * take the slowpath. Only changing fb or position should be
> +	 * in the fastpath.
> +	 */
> +	if (old_plane_state->crtc != crtc ||
> +	    old_plane_state->src_w != src_w ||
> +	    old_plane_state->src_h != src_h ||
> +	    old_plane_state->crtc_w != crtc_w ||
> +	    old_plane_state->crtc_h != crtc_h ||
> +	    !old_plane_state->visible ||
> +	    old_plane_state->fb->modifier != fb->modifier)
> +		goto slow;
> +
> +	new_plane_state = intel_plane_duplicate_state(plane);
> +	if (!new_plane_state)
> +		return -ENOMEM;

About creating a new plane state here and swapping it later, I guess
it's more for the sake of intel_plane_atomic_check_with_state() to go
through cleanly, right? Rather than directly modifying the old plane
state?

I didn't see anything equivalent in vc4's implementation of
update_plane, hence was wondering why exactly it is needed.

Also, about updating fb in the fast path, my assumption was
that it was only crtc_x/y was the thing most likely to be
changed really fast. Have you seen use cases where the fb
changes at a faster than vsync rate?

Thanks,
Archit

> +
> +	drm_atomic_set_fb_for_plane(new_plane_state, fb);
> +
> +	new_plane_state->src_x = src_x;
> +	new_plane_state->src_y = src_y;
> +	new_plane_state->src_w = src_w;
> +	new_plane_state->src_h = src_h;
> +	new_plane_state->crtc_x = crtc_x;
> +	new_plane_state->crtc_y = crtc_y;
> +	new_plane_state->crtc_w = crtc_w;
> +	new_plane_state->crtc_h = crtc_h;
> +
> +	ret = intel_plane_atomic_check_with_state(to_intel_crtc_state(crtc->state),
> +						  to_intel_plane_state(new_plane_state));
> +	if (ret)
> +		goto out_free;
> +
> +	/* Visibility changed, must take slowpath. */
> +	if (!new_plane_state->visible)
> +		goto slow_free;
> +
> +	ret = mutex_lock_interruptible(&dev_priv->drm.struct_mutex);
> +	if (ret)
> +		goto out_free;
> +
> +	if (INTEL_INFO(dev_priv)->cursor_needs_physical) {
> +		int align = IS_I830(dev_priv) ? 16 * 1024 : 256;
> +
> +		ret = i915_gem_object_attach_phys(intel_fb_obj(fb), align);
> +		if (ret) {
> +			DRM_DEBUG_KMS("failed to attach phys object\n");
> +			goto out_unlock;
> +		}
> +	} else {
> +		struct i915_vma *vma;
> +
> +		vma = intel_pin_and_fence_fb_obj(fb, new_plane_state->rotation);
> +		if (IS_ERR(vma)) {
> +			DRM_DEBUG_KMS("failed to pin object\n");
> +
> +			ret = PTR_ERR(vma);
> +			goto out_unlock;
> +		}
> +	}
> +
> +	old_fb = old_plane_state->fb;
> +
> +	i915_gem_track_fb(intel_fb_obj(old_fb), intel_fb_obj(fb),
> +			  intel_plane->frontbuffer_bit);
> +
> +	/* Swap plane state */
> +	new_plane_state->fence = old_plane_state->fence;
> +	*to_intel_plane_state(old_plane_state) = *to_intel_plane_state(new_plane_state);
> +	new_plane_state->fence = NULL;
> +	new_plane_state->fb = old_fb;
> +
> +	intel_plane->update_plane(plane,
> +				  to_intel_crtc_state(crtc->state),
> +				  to_intel_plane_state(plane->state));
> +
> +	intel_cleanup_plane_fb(plane, new_plane_state);
> +
> +out_unlock:
> +	mutex_unlock(&dev_priv->drm.struct_mutex);
> +out_free:
> +	intel_plane_destroy_state(plane, new_plane_state);
> +	return ret;
> +
> +slow_free:
> +	intel_plane_destroy_state(plane, new_plane_state);
> +slow:
> +	return drm_atomic_helper_update_plane(plane, crtc, fb,
> +					      crtc_x, crtc_y, crtc_w, crtc_h,
> +					      src_x, src_y, src_w, src_h);
> +}
> +
> +static const struct drm_plane_funcs intel_cursor_plane_funcs = {
> +	.update_plane = intel_legacy_cursor_update,
> +	.disable_plane = drm_atomic_helper_disable_plane,
> +	.destroy = intel_plane_destroy,
> +	.set_property = drm_atomic_helper_plane_set_property,
> +	.atomic_get_property = intel_plane_atomic_get_property,
> +	.atomic_set_property = intel_plane_atomic_set_property,
> +	.atomic_duplicate_state = intel_plane_duplicate_state,
> +	.atomic_destroy_state = intel_plane_destroy_state,
> +};
> +
>  static struct intel_plane *
>  intel_primary_plane_create(struct drm_i915_private *dev_priv, enum pipe pipe)
>  {
> @@ -15274,7 +15404,7 @@ intel_cursor_plane_create(struct drm_i915_private *dev_priv, enum pipe pipe)
>  	cursor->disable_plane = intel_disable_cursor_plane;
>
>  	ret = drm_universal_plane_init(&dev_priv->drm, &cursor->base,
> -				       0, &intel_plane_funcs,
> +				       0, &intel_cursor_plane_funcs,
>  				       intel_cursor_formats,
>  				       ARRAY_SIZE(intel_cursor_formats),
>  				       DRM_PLANE_TYPE_CURSOR,
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 8f4ddca0f521..8b6f39506d45 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1844,6 +1844,8 @@ struct drm_plane_state *intel_plane_duplicate_state(struct drm_plane *plane);
>  void intel_plane_destroy_state(struct drm_plane *plane,
>  			       struct drm_plane_state *state);
>  extern const struct drm_plane_helper_funcs intel_plane_helper_funcs;
> +int intel_plane_atomic_check_with_state(struct intel_crtc_state *crtc_state,
> +					struct intel_plane_state *intel_state);
>
>  /* intel_color.c */
>  void intel_color_init(struct drm_crtc *crtc);
>

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