Re: [PATCH v2 05/10] drm/i915/gen9: Get rid of redundant watermark values

[Paulo Zanoni <paulo.r.zanoni@intel.com>]

Em Qui, 2016-10-13 às 15:39 +0200, Maarten Lankhorst escreveu:
> Op 08-10-16 om 02:11 schreef Lyude:
> > 
> > Now that we've make skl_wm_levels make a little more sense, we can
> > remove all of the redundant wm information. Up until now we'd been
> > storing two copies of all of the skl watermarks: one being the
> > skl_pipe_wm structs, the other being the global wm struct in
> > drm_i915_private containing the raw register values. This is
> > confusing
> > and problematic, since it means we're prone to accidentally letting
> > the
> > two copies go out of sync. So, get rid of all of the functions
> > responsible for computing the register values and just use a single
> > helper, skl_write_wm_level(), to convert and write the new
> > watermarks on
> > the fly.
> > 
> > Changes since v1:
> > - Fixup skl_write_wm_level()
> > - Fixup skl_wm_level_from_reg_val()
> > - Don't forget to copy *active to intel_crtc->wm.active.skl
> > 
> > Signed-off-by: Lyude <cpaul@redhat.com>
> > Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_drv.h      |   2 -
> >  drivers/gpu/drm/i915/intel_display.c |  14 ++-
> >  drivers/gpu/drm/i915/intel_drv.h     |   6 +-
> >  drivers/gpu/drm/i915/intel_pm.c      | 204 ++++++++++++-----------
> > ------------
> >  drivers/gpu/drm/i915/intel_sprite.c  |   8 +-
> >  5 files changed, 90 insertions(+), 144 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h
> > b/drivers/gpu/drm/i915/i915_drv.h
> > index 0287c93..76583b2 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -1644,8 +1644,6 @@ struct skl_ddb_allocation {
> >  struct skl_wm_values {
> >  	unsigned dirty_pipes;
> >  	struct skl_ddb_allocation ddb;
> > -	uint32_t plane[I915_MAX_PIPES][I915_MAX_PLANES][8];
> > -	uint32_t plane_trans[I915_MAX_PIPES][I915_MAX_PLANES];
> >  };
> >  
> >  struct skl_wm_level {
> > diff --git a/drivers/gpu/drm/i915/intel_display.c
> > b/drivers/gpu/drm/i915/intel_display.c
> > index a71d05a..39400a0 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -3378,6 +3378,8 @@ static void
> > skylake_update_primary_plane(struct drm_plane *plane,
> >  	struct intel_crtc *intel_crtc = to_intel_crtc(crtc_state-
> > >base.crtc);
> >  	struct drm_framebuffer *fb = plane_state->base.fb;
> >  	const struct skl_wm_values *wm = &dev_priv-
> > >wm.skl_results;
> > +	const struct skl_plane_wm *p_wm =
> > +		&crtc_state->wm.skl.optimal.planes[0];
> >  	int pipe = intel_crtc->pipe;
> >  	u32 plane_ctl;
> >  	unsigned int rotation = plane_state->base.rotation;
> > @@ -3414,7 +3416,7 @@ static void
> > skylake_update_primary_plane(struct drm_plane *plane,
> >  	intel_crtc->adjusted_y = src_y;
> >  
> >  	if (wm->dirty_pipes & drm_crtc_mask(&intel_crtc->base))
> > -		skl_write_plane_wm(intel_crtc, wm, 0);
> > +		skl_write_plane_wm(intel_crtc, p_wm, &wm->ddb, 0);
> >  
> >  	I915_WRITE(PLANE_CTL(pipe, 0), plane_ctl);
> >  	I915_WRITE(PLANE_OFFSET(pipe, 0), (src_y << 16) | src_x);
> > @@ -3448,6 +3450,8 @@ static void
> > skylake_disable_primary_plane(struct drm_plane *primary,
> >  	struct drm_device *dev = crtc->dev;
> >  	struct drm_i915_private *dev_priv = to_i915(dev);
> >  	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> > +	struct intel_crtc_state *cstate =
> > to_intel_crtc_state(crtc->state);
> > +	const struct skl_plane_wm *p_wm = &cstate-
> > >wm.skl.optimal.planes[0];
> >  	int pipe = intel_crtc->pipe;
> >  
> >  	/*
> > @@ -3455,7 +3459,8 @@ static void
> > skylake_disable_primary_plane(struct drm_plane *primary,
> >  	 * plane's visiblity isn't actually changing neither is
> > its watermarks.
> >  	 */
> >  	if (!crtc->primary->state->visible)
> > -		skl_write_plane_wm(intel_crtc, &dev_priv-
> > >wm.skl_results, 0);
> > +		skl_write_plane_wm(intel_crtc, p_wm,
> > +				   &dev_priv->wm.skl_results.ddb,
> > 0);
> >  
> >  	I915_WRITE(PLANE_CTL(pipe, 0), 0);
> >  	I915_WRITE(PLANE_SURF(pipe, 0), 0);
> > @@ -10819,12 +10824,15 @@ static void i9xx_update_cursor(struct
> > drm_crtc *crtc, u32 base,
> >  	struct drm_device *dev = crtc->dev;
> >  	struct drm_i915_private *dev_priv = to_i915(dev);
> >  	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> > +	struct intel_crtc_state *cstate =
> > to_intel_crtc_state(crtc->state);
> >  	const struct skl_wm_values *wm = &dev_priv-
> > >wm.skl_results;
> > +	const struct skl_plane_wm *p_wm =
> > +		&cstate->wm.skl.optimal.planes[PLANE_CURSOR];
> >  	int pipe = intel_crtc->pipe;
> >  	uint32_t cntl = 0;
> >  
> >  	if (INTEL_GEN(dev_priv) >= 9 && wm->dirty_pipes &
> > drm_crtc_mask(crtc))
> > -		skl_write_cursor_wm(intel_crtc, wm);
> > +		skl_write_cursor_wm(intel_crtc, p_wm, &wm->ddb);
> >  
> >  	if (plane_state && plane_state->base.visible) {
> >  		cntl = MCURSOR_GAMMA_ENABLE;
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h
> > b/drivers/gpu/drm/i915/intel_drv.h
> > index d684f4f..958dc72 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -1765,9 +1765,11 @@ bool skl_ddb_allocation_equals(const struct
> > skl_ddb_allocation *old,
> >  bool skl_ddb_allocation_overlaps(struct drm_atomic_state *state,
> >  				 struct intel_crtc *intel_crtc);
> >  void skl_write_cursor_wm(struct intel_crtc *intel_crtc,
> > -			 const struct skl_wm_values *wm);
> > +			 const struct skl_plane_wm *wm,
> > +			 const struct skl_ddb_allocation *ddb);
> >  void skl_write_plane_wm(struct intel_crtc *intel_crtc,
> > -			const struct skl_wm_values *wm,
> > +			const struct skl_plane_wm *wm,
> > +			const struct skl_ddb_allocation *ddb,
> >  			int plane);
> >  uint32_t ilk_pipe_pixel_rate(const struct intel_crtc_state
> > *pipe_config);
> >  bool ilk_disable_lp_wm(struct drm_device *dev);
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c
> > b/drivers/gpu/drm/i915/intel_pm.c
> > index 5dbaf12..5cb537c 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -3000,6 +3000,8 @@ bool intel_can_enable_sagv(struct
> > drm_atomic_state *state)
> >  	struct drm_i915_private *dev_priv = to_i915(dev);
> >  	struct intel_atomic_state *intel_state =
> > to_intel_atomic_state(state);
> >  	struct drm_crtc *crtc;
> > +	struct intel_crtc_state *cstate;
> > +	struct skl_plane_wm *wm;
> >  	enum pipe pipe;
> >  	int level, plane;
> >  
> > @@ -3020,18 +3022,21 @@ bool intel_can_enable_sagv(struct
> > drm_atomic_state *state)
> >  	/* Since we're now guaranteed to only have one active
> > CRTC... */
> >  	pipe = ffs(intel_state->active_crtcs) - 1;
> >  	crtc = dev_priv->pipe_to_crtc_mapping[pipe];
> > +	cstate = intel_atomic_get_crtc_state(state,
> > to_intel_crtc(crtc));
> Wrong cstate here, should be crtc->state since it's committed and
> crtc_state is the old state.

Ah... How many instances of the "you're looking at the wrong state
struct" have we spotted/fixed ever since the introduction of the atomic
code? Can't we try to do something more human-proof in order to avoid
these problems from happening again and again?

Like for example copying the old states to a specific structure like
drm_atomic_state->old_states_which_you_probably_shouldn_be_using, and
then setting the CRTC/connector/plane states in the drm_atomic_state
struct to NULL so bugs will be much easier to spot?

Anyway, with this problem fixed, feel free to add:
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>

> 
> ~Maarten
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