Re: [PATCH v2 3/4] drm/i915: Enabling constant alpha drm property

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Apr 15, 2014 at 03:14:04PM +0530, Sagar Arun Kamble wrote:
> Hi Ville,
> 
> Somehow I did not receive your review comments
> (http://lists.freedesktop.org/archives/intel-gfx/2014-April/042956.html
> ) in my mailbox.
> 
> Here is my input w.r.t patches I have sent for review:
> 
> Currently my patches are modeling constant alpha blend factor (assuming
> pre-multiplied format) as 
> 
> Dc = Sc * Ca + (1 - Ca) * Dc
> 
> User space has to supply (<alpha value>, CONSTANT_ALPHA) through drm
> property to invoke this blending.
> 
> Here are my queries on your proposed approach:
> 
> 1. src factors are 1, Ca, Sa*Ca and dst factors are 0, 1-Ca, 1-Sa,
> 1-Sa*Ca: How is factor 0 derived and applicable to Dst and not
> applicable to src.

If blending is disabled the function will be Dc = Sc * 1 + 0 * Dc

Hence we get the ONE and ZERO blend factors.

> 
> 2. With this approach user will know what blend equation is supported.
> How does user supply the blend parameters? Should we have another
> property that will have blend equation selected and corresponding
> parameters?

By parameters you mean the constant alpha and background color for
instance? I think having those as separate properties is the cleanest
option.

> 
> 3. Is flag suggested for pre-multiply ("yes please, premultiply the data
> for me") to be set during AddFB?

If we define the flag that way, then I think we should make it part of
the blend equation rather than apply it to the FB. Or it could even be
a separate plane property. 

> 
> Kindly check my patches and provide feedback on the approach of stuffing
> blend type and blend parameter into single 64bit drm property.

I think we should avoid trying to stuff too much data into a single
property. IMO blend equation can be one property, constant alpha,
background color, pre-multiplication may be other properties.

> 
> 
> Thanks,
> Sagar
> 
> 
> 
> 
> On Thu, 2014-04-03 at 11:13 +0530, Sagar Arun Kamble wrote:
> > Hi Ville,
> > 
> > Could you please review these patches.
> > 
> > thanks,
> > Sagar
> > 
> > 
> > On Wed, 2014-04-02 at 11:42 +0530, Sagar Arun Kamble wrote:
> > > Reminder for review :)
> > > 
> > > On Tue, 2014-04-01 at 10:21 +0530, Sagar Arun Kamble wrote:
> > > > Gentle Reminder for reviewing this and related patches:
> > > > http://lists.freedesktop.org/archives/intel-gfx/2014-March/042350.html
> > > > http://lists.freedesktop.org/archives/intel-gfx/2014-March/042351.html
> > > > http://lists.freedesktop.org/archives/intel-gfx/2014-March/042352.html
> > > > http://lists.freedesktop.org/archives/intel-gfx/2014-March/042587.html
> > > > http://lists.freedesktop.org/archives/intel-gfx/2014-March/042354.html
> > > > 
> > > > 
> > > > Also, provide views on "how do we handle pre-multiplied alpha pixel
> > > > formats or is there need to convey pre-multiplied alpha pixel format
> > > > through additional drm property?"
> > > > Since we are already advertising supported pre-multiplied formats
> > > > during intel_plane_init/drm_plane_init by supplying vlv_plane_formats
> > > > etc.
> > > > 
> > > > 
> > > > On Tue, 2014-03-25 at 20:02 +0530, sagar.a.kamble@intel.com wrote:
> > > > > From: Sagar Kamble <sagar.a.kamble@intel.com>
> > > > > 
> > > > > This patch enables constant alpha property for Sprite planes.
> > > > > Client has to set BIT(DRM_BLEND_CONSTANT_ALPHA) | ((alpha value) << 32)
> > > > > for applying constant alpha on a plane. To disable constant alpha,
> > > > > client has to set BIT(DRM_BLEND_SRC_COLOR)
> > > > > 
> > > > > v2: Fixing property value comparison in vlv_update_plane with the use
> > > > > of BIT(). Replacing DRM_BLEND_NONE by DRM_BLEND_SRC_COLOR.
> > > > > Reverting line spacing change in i915_driver_lastclose. Return value
> > > > > of intel_plane_set_property is changed to -ENVAL [Damien's Review Comments]
> > > > > 
> > > > > Testcase: igt/kms_blend
> > > > > Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> > > > > Cc: Jani Nikula <jani.nikula@linux.intel.com>
> > > > > Signed-off-by: Sagar Kamble <sagar.a.kamble@intel.com>
> > > > > Tested-by: Sharma, Ankitprasad R <ankitprasad.r.sharma@intel.com>
> > > > > ---
> > > > >  drivers/gpu/drm/i915/i915_dma.c     | 10 ++++++
> > > > >  drivers/gpu/drm/i915/i915_drv.h     |  1 +
> > > > >  drivers/gpu/drm/i915/i915_reg.h     |  2 ++
> > > > >  drivers/gpu/drm/i915/intel_drv.h    |  7 +++++
> > > > >  drivers/gpu/drm/i915/intel_sprite.c | 61 ++++++++++++++++++++++++++++++++++++-
> > > > >  5 files changed, 80 insertions(+), 1 deletion(-)
> > > > > 
> > > > > diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> > > > > index e4d2b9f..e3a94a3 100644
> > > > > --- a/drivers/gpu/drm/i915/i915_dma.c
> > > > > +++ b/drivers/gpu/drm/i915/i915_dma.c
> > > > > @@ -1898,12 +1898,22 @@ void i915_driver_lastclose(struct drm_device * dev)
> > > > >  {
> > > > >  	drm_i915_private_t *dev_priv = dev->dev_private;
> > > > >  
> > > > > +	struct intel_plane *plane;
> > > > >  	/* On gen6+ we refuse to init without kms enabled, but then the drm core
> > > > >  	 * goes right around and calls lastclose. Check for this and don't clean
> > > > >  	 * up anything. */
> > > > >  	if (!dev_priv)
> > > > >  		return;
> > > > >  
> > > > > +	if (dev_priv->blend_property) {
> > > > > +		list_for_each_entry(plane, &dev->mode_config.plane_list, base.head) {
> > > > > +			plane->blend_param.value = BIT(DRM_BLEND_SRC_COLOR);
> > > > > +			drm_object_property_set_value(&plane->base.base,
> > > > > +						dev_priv->blend_property,
> > > > > +						plane->blend_param.value);
> > > > > +		}
> > > > > +	}
> > > > > +
> > > > >  	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> > > > >  		intel_fbdev_restore_mode(dev);
> > > > >  		vga_switcheroo_process_delayed_switch();
> > > > > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> > > > > index 70fbe90..0d1be70 100644
> > > > > --- a/drivers/gpu/drm/i915/i915_drv.h
> > > > > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > > > > @@ -1607,6 +1607,7 @@ typedef struct drm_i915_private {
> > > > >  
> > > > >  	struct drm_property *broadcast_rgb_property;
> > > > >  	struct drm_property *force_audio_property;
> > > > > +	struct drm_property *blend_property;
> > > > >  
> > > > >  	uint32_t hw_context_size;
> > > > >  	struct list_head context_list;
> > > > > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > > > > index 6174fda..bfcfe72 100644
> > > > > --- a/drivers/gpu/drm/i915/i915_reg.h
> > > > > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > > > > @@ -3774,6 +3774,8 @@ enum punit_power_well {
> > > > >  #define   SPRITE_INT_GAMMA_ENABLE	(1<<13)
> > > > >  #define   SPRITE_TILED			(1<<10)
> > > > >  #define   SPRITE_DEST_KEY		(1<<2)
> > > > > +#define	  SPRITE_CONSTANT_ALPHA_ENABLE  (1<<31)
> > > > > +#define   SPRITE_CONSTANT_ALPHA_MASK	(0xFF)
> > > > >  #define _SPRA_LINOFF		0x70284
> > > > >  #define _SPRA_STRIDE		0x70288
> > > > >  #define _SPRA_POS		0x7028c
> > > > > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > > > > index f4e0615..039a800 100644
> > > > > --- a/drivers/gpu/drm/i915/intel_drv.h
> > > > > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > > > > @@ -409,6 +409,13 @@ struct intel_plane {
> > > > >  	unsigned int crtc_w, crtc_h;
> > > > >  	uint32_t src_x, src_y;
> > > > >  	uint32_t src_w, src_h;
> > > > > +	union {
> > > > > +		uint64_t value;
> > > > > +		struct {
> > > > > +			unsigned int type;
> > > > > +			unsigned int factor;
> > > > > +		} details;
> > > > > +	} blend_param;
> > > > >  
> > > > >  	/* Since we need to change the watermarks before/after
> > > > >  	 * enabling/disabling the planes, we need to store the parameters here
> > > > > diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
> > > > > index 9436f18..9ec84bb 100644
> > > > > --- a/drivers/gpu/drm/i915/intel_sprite.c
> > > > > +++ b/drivers/gpu/drm/i915/intel_sprite.c
> > > > > @@ -51,11 +51,15 @@ vlv_update_plane(struct drm_plane *dplane, struct drm_crtc *crtc,
> > > > >  	int pipe = intel_plane->pipe;
> > > > >  	int plane = intel_plane->plane;
> > > > >  	u32 sprctl;
> > > > > +	u32 sprconstalpha;
> > > > > +	unsigned int blend_type, blend_factor;
> > > > >  	unsigned long sprsurf_offset, linear_offset;
> > > > >  	int pixel_size = drm_format_plane_cpp(fb->pixel_format, 0);
> > > > >  
> > > > >  	sprctl = I915_READ(SPCNTR(pipe, plane));
> > > > >  
> > > > > +	sprconstalpha = SPCONSTALPHA(pipe, plane);
> > > > > +
> > > > >  	/* Mask out pixel format bits in case we change it */
> > > > >  	sprctl &= ~SP_PIXFORMAT_MASK;
> > > > >  	sprctl &= ~SP_YUV_BYTE_ORDER_MASK;
> > > > > @@ -104,6 +108,23 @@ vlv_update_plane(struct drm_plane *dplane, struct drm_crtc *crtc,
> > > > >  		break;
> > > > >  	}
> > > > >  
> > > > > +	/* Handle plane alpha and color blending properties */
> > > > > +	blend_type = intel_plane->blend_param.details.type;
> > > > > +	blend_factor = intel_plane->blend_param.details.factor;
> > > > > +
> > > > > +	switch (blend_type) {
> > > > > +	case BIT(DRM_BLEND_SRC_COLOR):
> > > > > +		I915_WRITE(sprconstalpha, ~SPRITE_CONSTANT_ALPHA_ENABLE);
> > > > > +		break;
> > > > > +	case BIT(DRM_BLEND_CONSTANT_ALPHA):
> > > > > +		I915_WRITE(sprconstalpha, (blend_factor & SPRITE_CONSTANT_ALPHA_MASK) |
> > > > > +						SPRITE_CONSTANT_ALPHA_ENABLE);
> > > > > +		break;
> > > > > +	default:
> > > > > +		DRM_DEBUG_DRIVER("%x Blending operation not supported", intel_plane->blend_param.details.type);
> > > > > +		break;
> > > > > +	}
> > > > > +
> > > > >  	/*
> > > > >  	 * Enable gamma to match primary/cursor plane behaviour.
> > > > >  	 * FIXME should be user controllable via propertiesa.
> > > > > @@ -1011,6 +1032,26 @@ out_unlock:
> > > > >  	return ret;
> > > > >  }
> > > > >  
> > > > > +static int intel_plane_set_property(struct drm_plane *plane,
> > > > > +				    struct drm_property *prop,
> > > > > +				    uint64_t val)
> > > > > +{
> > > > > +	struct drm_i915_private *dev_priv = plane->dev->dev_private;
> > > > > +	struct intel_plane *intel_plane = to_intel_plane(plane);
> > > > > +	uint64_t old_val;
> > > > > +	int ret = -EINVAL;
> > > > > +
> > > > > +	if (prop == dev_priv->blend_property) {
> > > > > +		old_val = intel_plane->blend_param.value;
> > > > > +		intel_plane->blend_param.value = val;
> > > > > +		ret = intel_plane_restore(plane);
> > > > > +		if (ret)
> > > > > +			intel_plane->blend_param.value = old_val;
> > > > > +	}
> > > > > +
> > > > > +	return ret;
> > > > > +}
> > > > > +
> > > > >  int intel_plane_restore(struct drm_plane *plane)
> > > > >  {
> > > > >  	struct intel_plane *intel_plane = to_intel_plane(plane);
> > > > > @@ -1037,6 +1078,7 @@ static const struct drm_plane_funcs intel_plane_funcs = {
> > > > >  	.update_plane = intel_update_plane,
> > > > >  	.disable_plane = intel_disable_plane,
> > > > >  	.destroy = intel_destroy_plane,
> > > > > +	.set_property = intel_plane_set_property,
> > > > >  };
> > > > >  
> > > > >  static uint32_t ilk_plane_formats[] = {
> > > > > @@ -1073,6 +1115,7 @@ static uint32_t vlv_plane_formats[] = {
> > > > >  int
> > > > >  intel_plane_init(struct drm_device *dev, enum pipe pipe, int plane)
> > > > >  {
> > > > > +	struct drm_i915_private *dev_priv = dev->dev_private;
> > > > >  	struct intel_plane *intel_plane;
> > > > >  	unsigned long possible_crtcs;
> > > > >  	const uint32_t *plane_formats;
> > > > > @@ -1141,13 +1184,29 @@ intel_plane_init(struct drm_device *dev, enum pipe pipe, int plane)
> > > > >  
> > > > >  	intel_plane->pipe = pipe;
> > > > >  	intel_plane->plane = plane;
> > > > > +	/* Initialize drm properties for plane */
> > > > > +	intel_plane->blend_param.details.type = BIT(DRM_BLEND_SRC_COLOR);
> > > > > +	intel_plane->blend_param.details.factor = 0;
> > > > > +
> > > > >  	possible_crtcs = (1 << pipe);
> > > > >  	ret = drm_plane_init(dev, &intel_plane->base, possible_crtcs,
> > > > >  			     &intel_plane_funcs,
> > > > >  			     plane_formats, num_plane_formats,
> > > > >  			     false);
> > > > > -	if (ret)
> > > > > +	if (ret) {
> > > > >  		kfree(intel_plane);
> > > > > +		goto out;
> > > > > +	}
> > > > > +
> > > > > +	if (!dev_priv->blend_property)
> > > > > +		dev_priv->blend_property = drm_mode_create_blend_property(dev,
> > > > > +							BIT(DRM_BLEND_SRC_COLOR) |
> > > > > +							BIT(DRM_BLEND_CONSTANT_ALPHA));
> > > > >  
> > > > > +	if (dev_priv->blend_property)
> > > > > +		drm_object_attach_property(&intel_plane->base.base,
> > > > > +				dev_priv->blend_property,
> > > > > +				intel_plane->blend_param.value);
> > > > > +out:
> > > > >  	return ret;
> > > > >  }
> > > > 
> > > 
> > 
> 

-- 
Ville Syrjälä
Intel OTC