[Intel-gfx] [PATCH 3/7] drm/i915/display: Add new fb_op_origin type and use it to optimize power savings

Souza, Jose jose.souza at intel.com
Fri Sep 24 17:11:50 UTC 2021 

On Fri, 2021-09-24 at 17:39 +0300, Ville Syrjälä wrote:
> On Thu, Sep 23, 2021 at 12:46:13PM -0700, José Roberto de Souza wrote:
> > intel_prepare_plane_fb() was calling i915_gem_object_flush_frontbuffer()
> > with the generic ORIGIN_DIRTYFB, what was causing
> > PSR, FBC and DRRS to do their frontbuffer rendering in a framebuffer
> > that will be flipped.
> > 
> > Not handling this call as frontbuffer rendering allow us to save
> > more power with all 3 features.
> > 
> > Same applies when allocating a framebuffer for fbdev emulation, after
> > allocation userspace will draw on it and trigger invaldate/flush calls
> > with ORIGIN_DIRTYFB.
> > 
> > Cc: Gwan-gyeong Mun <gwan-gyeong.mun at intel.com>
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_display.c     | 2 +-
> >  drivers/gpu/drm/i915/display/intel_drrs.c        | 5 ++++-
> >  drivers/gpu/drm/i915/display/intel_drrs.h        | 4 +++-
> >  drivers/gpu/drm/i915/display/intel_fbc.c         | 2 +-
> >  drivers/gpu/drm/i915/display/intel_fbdev.c       | 2 +-
> >  drivers/gpu/drm/i915/display/intel_frontbuffer.c | 2 +-
> >  drivers/gpu/drm/i915/display/intel_frontbuffer.h | 1 +
> >  drivers/gpu/drm/i915/display/intel_psr.c         | 5 ++++-
> >  8 files changed, 16 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> > index f27c294beb926..ecf8c69473e38 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > @@ -10666,7 +10666,7 @@ intel_prepare_plane_fb(struct drm_plane *_plane,
> >  		return ret;
> >  
> >  	i915_gem_object_wait_priority(obj, 0, &attr);
> > -	i915_gem_object_flush_frontbuffer(obj, ORIGIN_DIRTYFB);
> > +	i915_gem_object_flush_frontbuffer(obj, ORIGIN_PREPARE_FB);
> 
> I think this should just get nuked. See
> https://patchwork.freedesktop.org/patch/432166/?series=89824&rev=1
> 
> Unfortunately I wasn't able to get past glk's semi-borked
> FBC with that yet.

Cool, will try to nuke it.
This series passed in BAT and shards, hopefully we will not hit this issue today. 

> 
> >  
> >  	if (!new_plane_state->uapi.fence) { /* implicit fencing */
> >  		struct dma_fence *fence;
> > diff --git a/drivers/gpu/drm/i915/display/intel_drrs.c b/drivers/gpu/drm/i915/display/intel_drrs.c
> > index c1439fcb5a959..46828222a098b 100644
> > --- a/drivers/gpu/drm/i915/display/intel_drrs.c
> > +++ b/drivers/gpu/drm/i915/display/intel_drrs.c
> > @@ -373,8 +373,11 @@ void intel_drrs_invalidate(struct drm_i915_private *dev_priv,
> >   * Dirty frontbuffers relevant to DRRS are tracked in busy_frontbuffer_bits.
> >   */
> >  void intel_drrs_flush(struct drm_i915_private *dev_priv,
> > -		      unsigned int frontbuffer_bits)
> > +		      unsigned int frontbuffer_bits, enum fb_op_origin origin)
> >  {
> > +	if (origin == ORIGIN_PREPARE_FB)
> > +		return;
> > +
> >  	intel_drrs_frontbuffer_update(dev_priv, frontbuffer_bits, false);
> >  }
> >  
> > diff --git a/drivers/gpu/drm/i915/display/intel_drrs.h b/drivers/gpu/drm/i915/display/intel_drrs.h
> > index 9ec9c447211af..e69528a98a9c2 100644
> > --- a/drivers/gpu/drm/i915/display/intel_drrs.h
> > +++ b/drivers/gpu/drm/i915/display/intel_drrs.h
> > @@ -8,6 +8,8 @@
> >  
> >  #include <linux/types.h>
> >  
> > +#include "intel_frontbuffer.h"
> > +
> >  struct drm_i915_private;
> >  struct intel_atomic_state;
> >  struct intel_crtc;
> > @@ -24,7 +26,7 @@ void intel_drrs_update(struct intel_dp *intel_dp,
> >  void intel_drrs_invalidate(struct drm_i915_private *dev_priv,
> >  			   unsigned int frontbuffer_bits);
> >  void intel_drrs_flush(struct drm_i915_private *dev_priv,
> > -		      unsigned int frontbuffer_bits);
> > +		      unsigned int frontbuffer_bits, enum fb_op_origin origin);
> >  void intel_drrs_page_flip(struct intel_atomic_state *state,
> >  			  struct intel_crtc *crtc);
> >  void intel_drrs_compute_config(struct intel_dp *intel_dp,
> > diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c
> > index b1c1a23c36be3..56c2de2994602 100644
> > --- a/drivers/gpu/drm/i915/display/intel_fbc.c
> > +++ b/drivers/gpu/drm/i915/display/intel_fbc.c
> > @@ -1155,7 +1155,7 @@ void intel_fbc_flush(struct drm_i915_private *dev_priv,
> >  
> >  	fbc->busy_bits &= ~frontbuffer_bits;
> >  
> > -	if (origin == ORIGIN_FLIP)
> > +	if (origin == ORIGIN_FLIP || origin == ORIGIN_PREPARE_FB)
> >  		goto out;
> >  
> >  	if (!fbc->busy_bits && fbc->crtc &&
> > diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c b/drivers/gpu/drm/i915/display/intel_fbdev.c
> > index 60d3ded270476..3097658938ae2 100644
> > --- a/drivers/gpu/drm/i915/display/intel_fbdev.c
> > +++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
> > @@ -230,7 +230,7 @@ static int intelfb_create(struct drm_fb_helper *helper,
> >  		goto out_unlock;
> >  	}
> >  
> > -	intel_frontbuffer_flush(to_frontbuffer(ifbdev), ORIGIN_DIRTYFB);
> > +	intel_frontbuffer_flush(to_frontbuffer(ifbdev), ORIGIN_PREPARE_FB);
> >  
> >  	info = drm_fb_helper_alloc_fbi(helper);
> >  	if (IS_ERR(info)) {
> > diff --git a/drivers/gpu/drm/i915/display/intel_frontbuffer.c b/drivers/gpu/drm/i915/display/intel_frontbuffer.c
> > index 0492446cd04ad..a88c147d6b523 100644
> > --- a/drivers/gpu/drm/i915/display/intel_frontbuffer.c
> > +++ b/drivers/gpu/drm/i915/display/intel_frontbuffer.c
> > @@ -92,7 +92,7 @@ static void frontbuffer_flush(struct drm_i915_private *i915,
> >  	trace_intel_frontbuffer_flush(frontbuffer_bits, origin);
> >  
> >  	might_sleep();
> > -	intel_drrs_flush(i915, frontbuffer_bits);
> > +	intel_drrs_flush(i915, frontbuffer_bits, origin);
> >  	intel_psr_flush(i915, frontbuffer_bits, origin);
> >  	intel_fbc_flush(i915, frontbuffer_bits, origin);
> >  }
> > diff --git a/drivers/gpu/drm/i915/display/intel_frontbuffer.h b/drivers/gpu/drm/i915/display/intel_frontbuffer.h
> > index 4b977c1e4d52b..950030950b0f9 100644
> > --- a/drivers/gpu/drm/i915/display/intel_frontbuffer.h
> > +++ b/drivers/gpu/drm/i915/display/intel_frontbuffer.h
> > @@ -37,6 +37,7 @@ enum fb_op_origin {
> >  	ORIGIN_CS,
> >  	ORIGIN_FLIP,
> >  	ORIGIN_DIRTYFB,
> > +	ORIGIN_PREPARE_FB,
> >  };
> >  
> >  struct intel_frontbuffer {
> > diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> > index ba2da689920f9..1cc4130dec7b1 100644
> > --- a/drivers/gpu/drm/i915/display/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> > @@ -2073,7 +2073,7 @@ void intel_psr_invalidate(struct drm_i915_private *dev_priv,
> >  {
> >  	struct intel_encoder *encoder;
> >  
> > -	if (origin == ORIGIN_FLIP)
> > +	if (origin == ORIGIN_FLIP || origin == ORIGIN_PREPARE_FB)
> >  		return;
> >  
> >  	for_each_intel_encoder_with_psr(&dev_priv->drm, encoder) {
> > @@ -2148,6 +2148,9 @@ void intel_psr_flush(struct drm_i915_private *dev_priv,
> >  {
> >  	struct intel_encoder *encoder;
> >  
> > +	if (origin == ORIGIN_PREPARE_FB)
> > +		return;
> > +
> >  	for_each_intel_encoder_with_psr(&dev_priv->drm, encoder) {
> >  		unsigned int pipe_frontbuffer_bits = frontbuffer_bits;
> >  		struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> > -- 
> > 2.33.0
>

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