Re: [RFC v2 3/7] drm/i915: update cursors asynchronously through atomic

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Gustavo Padovan <gustavo@padovan.org>
Cc: Gustavo Padovan <gustavo.padovan@collabora.com>,
	dri-devel@lists.freedesktop.org,
	Daniel Vetter <daniel.vetter@intel.com>
Subject: Re: [RFC v2 3/7] drm/i915: update cursors asynchronously through atomic
Date: Thu, 27 Apr 2017 18:41:00 +0300	[thread overview]
Message-ID: <20170427154100.GP30290@intel.com> (raw)
In-Reply-To: <20170427151519.8308-4-gustavo@padovan.org>

On Thu, Apr 27, 2017 at 12:15:15PM -0300, Gustavo Padovan wrote:
> From: Gustavo Padovan <gustavo.padovan@collabora.com>
> 
> Add support to async updates of cursors by using the new atomic
> interface for that. Basically what this commit does is do what
> intel_legacy_cursor_update() did but through atomic.
> 
> v2: move fb setting to core and use new state (Eric Anholt)
> 
> Cc: Daniel Vetter <daniel.vetter@intel.com>
> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
> ---
>  drivers/gpu/drm/i915/intel_atomic_plane.c |  52 +++++++++++
>  drivers/gpu/drm/i915/intel_display.c      | 147 +++++-------------------------
>  2 files changed, 73 insertions(+), 126 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_atomic_plane.c b/drivers/gpu/drm/i915/intel_atomic_plane.c
> index cfb4729..c5d0596 100644
> --- a/drivers/gpu/drm/i915/intel_atomic_plane.c
> +++ b/drivers/gpu/drm/i915/intel_atomic_plane.c
> @@ -246,11 +246,63 @@ static void intel_plane_atomic_update(struct drm_plane *plane,
>  	}
>  }
>  
> +static int intel_plane_atomic_async_check(struct drm_plane *plane,
> +					  struct drm_plane_state *state)
> +{
> +	struct drm_crtc *crtc = plane->state->crtc;
> +	struct drm_crtc_state *crtc_state = crtc->state;
> +
> +	if (plane->type != DRM_PLANE_TYPE_CURSOR)
> +		return -EINVAL;
> +
> +	/*
> +	 * When crtc is inactive or there is a modeset pending,
> +	 * wait for it to complete in the slowpath
> +	 */
> +	if (!crtc_state->active || to_intel_crtc_state(crtc_state)->update_pipe)
> +		return -EINVAL;
> +
> +	/* Only changing fb should be in the fastpath.  */

No, we want cursor movement there as well. It's somewhat impossible
to see from this code now that the core has the size checks. But even
so the comment should not lie.

> +	if (!plane->state->fb != !state->fb)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static void intel_plane_atomic_async_update(struct drm_plane *plane,
> +					    struct drm_plane_state *new_state)
> +{
> +	struct intel_plane *intel_plane = to_intel_plane(plane);
> +	struct drm_crtc *crtc = plane->state->crtc;
> +
> +	i915_gem_track_fb(intel_fb_obj(plane->state->fb),
> +			  intel_fb_obj(new_state->fb),
> +			  intel_plane->frontbuffer_bit);
> +
> +	*to_intel_plane_state(plane->state) = *to_intel_plane_state(new_state);
> +	to_intel_plane_state(new_state)->vma =
> +					to_intel_plane_state(plane->state)->vma;
> +
> +	plane->state->visible = new_state->visible;
> +
> +	if (plane->state->visible) {
> +		trace_intel_update_plane(plane, to_intel_crtc(crtc));
> +		intel_plane->update_plane(plane,
> +					  to_intel_crtc_state(crtc->state),
> +					  to_intel_plane_state(new_state));
> +	} else {
> +		trace_intel_disable_plane(plane, to_intel_crtc(crtc));
> +		intel_plane->disable_plane(plane, crtc);
> +	}
> +}
> +
>  const struct drm_plane_helper_funcs intel_plane_helper_funcs = {
>  	.prepare_fb = intel_prepare_plane_fb,
>  	.cleanup_fb = intel_cleanup_plane_fb,
>  	.atomic_check = intel_plane_atomic_check,
>  	.atomic_update = intel_plane_atomic_update,
> +	.atomic_async_check = intel_plane_atomic_async_check,
> +	.atomic_async_update = intel_plane_atomic_async_update,

NAK. We don't want these "async" updates for anything but cursors.

>  };
>  
>  /**
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index e217d04..c854c87 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -12993,13 +12993,29 @@ static int intel_atomic_commit(struct drm_device *dev,
>  	int ret = 0;
>  
>  	/*
> -	 * The intel_legacy_cursor_update() fast path takes care
> +	 * The atomic async update fast path takes care
>  	 * of avoiding the vblank waits for simple cursor
>  	 * movement and flips. For cursor on/off and size changes,
>  	 * we want to perform the vblank waits so that watermark
>  	 * updates happen during the correct frames. Gen9+ have
>  	 * double buffered watermarks and so shouldn't need this.
>  	 */
> +	if (state->async_update) {
> +		ret = mutex_lock_interruptible(&dev->struct_mutex);
> +		if (ret)
> +			return ret;
> +
> +		ret = drm_atomic_helper_prepare_planes(dev, state);
> +		mutex_unlock(&dev->struct_mutex);
> +
> +		drm_atomic_helper_async_commit(dev, state);
> +
> +		mutex_lock(&dev->struct_mutex);
> +		drm_atomic_helper_cleanup_planes(dev, state);
> +		mutex_unlock(&dev->struct_mutex);
> +		return 0;
> +	}
> +
>  	if (INTEL_GEN(dev_priv) < 9)
>  		state->legacy_cursor_update = false;
>  
> @@ -13141,6 +13157,9 @@ intel_prepare_plane_fb(struct drm_plane *plane,
>  		}
>  	}
>  
> +	if (new_state->state->async_update)
> +		return 0;
> +
>  	if (!obj && !old_obj)
>  		return 0;
>  
> @@ -13360,132 +13379,8 @@ 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_modeset_acquire_ctx *ctx)
> -{
> -	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;
> -	struct i915_vma *old_vma;
> -
> -	/*
> -	 * 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->fb != !fb)
> -		goto slow;
> -
> -	new_plane_state = intel_plane_duplicate_state(plane);
> -	if (!new_plane_state)
> -		return -ENOMEM;
> -
> -	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;
> -
> -	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;
> -		}
> -
> -		to_intel_plane_state(new_plane_state)->vma = vma;
> -	}
> -
> -	old_fb = old_plane_state->fb;
> -	old_vma = to_intel_plane_state(old_plane_state)->vma;
> -
> -	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;
> -	to_intel_plane_state(new_plane_state)->vma = old_vma;
> -
> -	if (plane->state->visible) {
> -		trace_intel_update_plane(plane, to_intel_crtc(crtc));
> -		intel_plane->update_plane(plane,
> -					  to_intel_crtc_state(crtc->state),
> -					  to_intel_plane_state(plane->state));
> -	} else {
> -		trace_intel_disable_plane(plane, to_intel_crtc(crtc));
> -		intel_plane->disable_plane(plane, crtc);
> -	}
> -
> -	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:
> -	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, ctx);
> -}
> -
>  static const struct drm_plane_funcs intel_cursor_plane_funcs = {
> -	.update_plane = intel_legacy_cursor_update,
> +	.update_plane = drm_atomic_helper_update_plane,
>  	.disable_plane = drm_atomic_helper_disable_plane,
>  	.destroy = intel_plane_destroy,
>  	.set_property = drm_atomic_helper_plane_set_property,
> -- 
> 2.9.3
> 
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-- 
Ville Syrjälä
Intel OTC
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