Re: [PATCH] drm/i915: Use enum plane_id for frontbuffer tracking

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

On Wed, Jan 24, 2018 at 04:16:19AM +0000, Pandiyan, Dhinakaran wrote:
> On Tue, 2018-01-23 at 20:33 +0200, Ville Syrjala wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > 
> > Replace the ad-hoc plane indexing scheme used by the frontbuffer
> > tracking with enum plane_id.
> > 
> > The old video overlay not being part of the plane_id namespace
> > will just be given the high bit.
> 
> I'm curious why the bit corresponding to PLANE_SPRITE0 is not re-used
> for the overlay. From a cursory read seems like platforms with overlays
> and sprites are mutually exclusive.

Currently yes, but maybe not in the future. I still have dreams of
exposing all the planes on these platforms, which would mean having
at least one sprite plane that's not the video overlay. I haven't
really figured out how to make it all work out nicely with enum
plane_id though as that's a per-pipe thing and the planes on the
old hw are not necessarily tied to a single pipe. Perhaps one
option would be to assign the plane ids globally, ie. PRIMARY==A,
PLANE1==B, PLANE2==C, etc. Not sure if that would actually work out
though.

> 
> Related question, how different is this overlay from the sprite planes?

Very different. I would like to expose it as a drm_plane eventually,
but there's a bit of actual work involved to convert the overlay
register updates to use mmio, and to handle the render cache
reconfiguration (which still involves stuffing MI commands to the
ring) in a decent way.

I do have a basic mmio conversion sitting on some branch somewhere,
but I don't think I got it to look as nice as I'd like. Plus it's
probably bitrotted enough by now that it needs some rework anyway.

> 
> 
> > 
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_drv.h      | 11 +++--------
> >  drivers/gpu/drm/i915/intel_display.c |  4 ++--
> >  drivers/gpu/drm/i915/intel_fbc.c     |  2 +-
> >  drivers/gpu/drm/i915/intel_sprite.c  |  4 +++-
> >  4 files changed, 9 insertions(+), 12 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> > index 8333692dac5a..bd545b1c9546 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -2404,16 +2404,11 @@ enum hdmi_force_audio {
> >   *
> >   * We have one bit per pipe and per scanout plane type.
> >   */
> > -#define INTEL_MAX_SPRITE_BITS_PER_PIPE 5
> >  #define INTEL_FRONTBUFFER_BITS_PER_PIPE 8
> > -#define INTEL_FRONTBUFFER_PRIMARY(pipe) \
> > -	(1 << (INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe)))
> > -#define INTEL_FRONTBUFFER_CURSOR(pipe) \
> > -	(1 << (1 + (INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe))))
> > -#define INTEL_FRONTBUFFER_SPRITE(pipe, plane) \
> > -	(1 << (2 + plane + (INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe))))
> > +#define INTEL_FRONTBUFFER(pipe, plane_id) \
> > +	(1 << ((plane_id) + INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe)))
> >  #define INTEL_FRONTBUFFER_OVERLAY(pipe) \
> > -	(1 << (2 + INTEL_MAX_SPRITE_BITS_PER_PIPE + (INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe))))
> > +	(1 << (INTEL_FRONTBUFFER_BITS_PER_PIPE - 1 + INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe)))
> >  #define INTEL_FRONTBUFFER_ALL_MASK(pipe) \
> >  	(0xff << (INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe)))
> >  
> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > index d585ce4c8732..3cc35add362f 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -13168,7 +13168,7 @@ intel_primary_plane_create(struct drm_i915_private *dev_priv, enum pipe pipe)
> >  	else
> >  		primary->i9xx_plane = (enum i9xx_plane_id) pipe;
> >  	primary->id = PLANE_PRIMARY;
> > -	primary->frontbuffer_bit = INTEL_FRONTBUFFER_PRIMARY(pipe);
> > +	primary->frontbuffer_bit = INTEL_FRONTBUFFER(pipe, primary->id);
> >  	primary->check_plane = intel_check_primary_plane;
> >  
> >  	if (INTEL_GEN(dev_priv) >= 9) {
> > @@ -13289,7 +13289,7 @@ intel_cursor_plane_create(struct drm_i915_private *dev_priv,
> >  	cursor->pipe = pipe;
> >  	cursor->i9xx_plane = (enum i9xx_plane_id) pipe;
> >  	cursor->id = PLANE_CURSOR;
> > -	cursor->frontbuffer_bit = INTEL_FRONTBUFFER_CURSOR(pipe);
> > +	cursor->frontbuffer_bit = INTEL_FRONTBUFFER(pipe, cursor->id);
> >  
> >  	if (IS_I845G(dev_priv) || IS_I865G(dev_priv)) {
> >  		cursor->update_plane = i845_update_cursor;
> > diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
> > index 9dc2b8b5f2db..a8a8a80497a8 100644
> > --- a/drivers/gpu/drm/i915/intel_fbc.c
> > +++ b/drivers/gpu/drm/i915/intel_fbc.c
> > @@ -1373,7 +1373,7 @@ void intel_fbc_init(struct drm_i915_private *dev_priv)
> >  
> >  	for_each_pipe(dev_priv, pipe) {
> >  		fbc->possible_framebuffer_bits |=
> > -				INTEL_FRONTBUFFER_PRIMARY(pipe);
> > +			INTEL_FRONTBUFFER(pipe, PLANE_PRIMARY);
> >  
> >  		if (fbc_on_pipe_a_only(dev_priv))
> >  			break;
> > diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
> > index a92c748ca8ab..18ef0392362e 100644
> > --- a/drivers/gpu/drm/i915/intel_sprite.c
> > +++ b/drivers/gpu/drm/i915/intel_sprite.c
> > @@ -345,6 +345,8 @@ skl_plane_get_hw_state(struct intel_plane *plane)
> >  	return ret;
> >  }
> >  
> > +
> > +
> >  static void
> >  chv_update_csc(struct intel_plane *plane, uint32_t format)
> >  {
> > @@ -1427,7 +1429,7 @@ intel_sprite_plane_create(struct drm_i915_private *dev_priv,
> >  	intel_plane->pipe = pipe;
> >  	intel_plane->i9xx_plane = plane;
> >  	intel_plane->id = PLANE_SPRITE0 + plane;
> > -	intel_plane->frontbuffer_bit = INTEL_FRONTBUFFER_SPRITE(pipe, plane);
> > +	intel_plane->frontbuffer_bit = INTEL_FRONTBUFFER(pipe, intel_plane->id);
> >  	intel_plane->check_plane = intel_check_sprite_plane;
> >  
> >  	possible_crtcs = (1 << pipe);

-- 
Ville Syrjälä
Intel OTC
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