[Intel-gfx] [PATCH v26 2/9] drm/i915: Use bw state for per crtc SAGV evaluation

Lisovskiy, Stanislav stanislav.lisovskiy at intel.com
Thu Apr 30 09:13:35 UTC 2020


On Thu, Apr 30, 2020 at 12:09:22PM +0300, Ville Syrjälä wrote:
> On Thu, Apr 23, 2020 at 10:58:55AM +0300, Stanislav Lisovskiy wrote:
> > Future platforms require per-crtc SAGV evaluation
> > and serializing global state when those are changed
> > from different commits.
> > 
> > v2: - Add has_sagv check to intel_crtc_can_enable_sagv
> >       so that it sets bit in reject mask.
> >     - Use bw_state in intel_pre/post_plane_enable_sagv
> >       instead of atomic state
> > 
> > v3: - Fixed rebase conflict, now using
> >       intel_atomic_crtc_state_for_each_plane_state in
> >       order to call it from atomic check
> > v4: - Use fb modifier from plane state
> > 
> > v5: - Make intel_has_sagv static again(Ville)
> >     - Removed unnecessary NULL assignments(Ville)
> >     - Removed unnecessary SAGV debug(Ville)
> >     - Call intel_compute_sagv_mask only for modesets(Ville)
> >     - Serialize global state only if sagv results change, but
> >       not mask itself(Ville)
> > 
> > v6: - use lock global state instead of serialize(Ville)
> 
> What I meant is that we need both. Serialize if sagv state is going to
> change, otherwise lock if the mask changes.

As I understand whenever we modify global state but not a real hw, we do
only global state locking - pipe sagv mask is not actually a hw, but just
a virtual thing. It affects the QGV points we enable and if it happens to
affect those in a way that those change - we'll any way have serialize
called from intel_bw.c. Thus shouldn't be an issue.

I can change it anyway of course.

Stan

> 
> > 
> > Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
> > Cc: Ville Syrjälä <ville.syrjala at intel.com>
> > Cc: James Ausmus <james.ausmus at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_bw.h |   6 ++
> >  drivers/gpu/drm/i915/intel_pm.c         | 113 ++++++++++++++++++------
> >  drivers/gpu/drm/i915/intel_pm.h         |   3 +-
> >  3 files changed, 93 insertions(+), 29 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_bw.h b/drivers/gpu/drm/i915/display/intel_bw.h
> > index ac004d6f4276..d6df91058223 100644
> > --- a/drivers/gpu/drm/i915/display/intel_bw.h
> > +++ b/drivers/gpu/drm/i915/display/intel_bw.h
> > @@ -18,6 +18,12 @@ struct intel_crtc_state;
> >  struct intel_bw_state {
> >  	struct intel_global_state base;
> >  
> > +	/*
> > +	 * Contains a bit mask, used to determine, whether correspondent
> > +	 * pipe allows SAGV or not.
> > +	 */
> > +	u8 pipe_sagv_reject;
> > +
> >  	unsigned int data_rate[I915_MAX_PIPES];
> >  	u8 num_active_planes[I915_MAX_PIPES];
> >  };
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > index 338a82577b76..7e15cf3368ad 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -43,6 +43,7 @@
> >  #include "i915_fixed.h"
> >  #include "i915_irq.h"
> >  #include "i915_trace.h"
> > +#include "display/intel_bw.h"
> >  #include "intel_pm.h"
> >  #include "intel_sideband.h"
> >  #include "../../../platform/x86/intel_ips.h"
> > @@ -3760,34 +3761,75 @@ intel_disable_sagv(struct drm_i915_private *dev_priv)
> >  void intel_sagv_pre_plane_update(struct intel_atomic_state *state)
> >  {
> >  	struct drm_i915_private *dev_priv = to_i915(state->base.dev);
> > +	const struct intel_bw_state *new_bw_state;
> >  
> > -	if (!intel_can_enable_sagv(state))
> > +	/*
> > +	 * Just return if we can't control SAGV or don't have it.
> > +	 * This is different from situation when we have SAGV but just can't
> > +	 * afford it due to DBuf limitation - in case if SAGV is completely
> > +	 * disabled in a BIOS, we are not even allowed to send a PCode request,
> > +	 * as it will throw an error. So have to check it here.
> > +	 */
> > +	if (!intel_has_sagv(dev_priv))
> > +		return;
> > +
> > +	new_bw_state = intel_atomic_get_new_bw_state(state);
> > +	if (!new_bw_state)
> > +		return;
> > +
> > +	if (!intel_can_enable_sagv(new_bw_state))
> >  		intel_disable_sagv(dev_priv);
> >  }
> >  
> >  void intel_sagv_post_plane_update(struct intel_atomic_state *state)
> >  {
> >  	struct drm_i915_private *dev_priv = to_i915(state->base.dev);
> > +	const struct intel_bw_state *new_bw_state;
> >  
> > -	if (intel_can_enable_sagv(state))
> > +	/*
> > +	 * Just return if we can't control SAGV or don't have it.
> > +	 * This is different from situation when we have SAGV but just can't
> > +	 * afford it due to DBuf limitation - in case if SAGV is completely
> > +	 * disabled in a BIOS, we are not even allowed to send a PCode request,
> > +	 * as it will throw an error. So have to check it here.
> > +	 */
> > +	if (!intel_has_sagv(dev_priv))
> > +		return;
> > +
> > +	new_bw_state = intel_atomic_get_new_bw_state(state);
> > +	if (!new_bw_state)
> > +		return;
> > +
> > +	if (intel_can_enable_sagv(new_bw_state))
> >  		intel_enable_sagv(dev_priv);
> >  }
> >  
> >  static bool intel_crtc_can_enable_sagv(const struct intel_crtc_state *crtc_state)
> >  {
> > -	struct drm_device *dev = crtc_state->uapi.crtc->dev;
> > -	struct drm_i915_private *dev_priv = to_i915(dev);
> > +	struct intel_atomic_state *state = to_intel_atomic_state(crtc_state->uapi.state);
> >  	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> > +	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> >  	struct intel_plane *plane;
> > +	const struct intel_plane_state *plane_state;
> >  	int level, latency;
> >  
> > +	if (!intel_has_sagv(dev_priv))
> > +		return false;
> > +
> >  	if (!crtc_state->hw.active)
> >  		return true;
> >  
> > +	/*
> > +	 * SKL+ workaround: bspec recommends we disable SAGV when we have
> > +	 * more then one pipe enabled
> > +	 */
> > +	if (hweight8(state->active_pipes) > 1)
> > +		return false;
> > +
> >  	if (crtc_state->hw.adjusted_mode.flags & DRM_MODE_FLAG_INTERLACE)
> >  		return false;
> >  
> > -	for_each_intel_plane_on_crtc(dev, crtc, plane) {
> > +	intel_atomic_crtc_state_for_each_plane_state(plane, plane_state, crtc_state) {
> >  		const struct skl_plane_wm *wm =
> >  			&crtc_state->wm.skl.optimal.planes[plane->id];
> >  
> > @@ -3803,7 +3845,7 @@ static bool intel_crtc_can_enable_sagv(const struct intel_crtc_state *crtc_state
> >  		latency = dev_priv->wm.skl_latency[level];
> >  
> >  		if (skl_needs_memory_bw_wa(dev_priv) &&
> > -		    plane->base.state->fb->modifier ==
> > +		    plane_state->uapi.fb->modifier ==
> >  		    I915_FORMAT_MOD_X_TILED)
> >  			latency += 15;
> >  
> > @@ -3819,35 +3861,44 @@ static bool intel_crtc_can_enable_sagv(const struct intel_crtc_state *crtc_state
> >  	return true;
> >  }
> >  
> > -bool intel_can_enable_sagv(struct intel_atomic_state *state)
> > +bool intel_can_enable_sagv(const struct intel_bw_state *bw_state)
> >  {
> > -	struct drm_i915_private *dev_priv = to_i915(state->base.dev);
> > +	return bw_state->pipe_sagv_reject == 0;
> > +}
> > +
> > +static int intel_compute_sagv_mask(struct intel_atomic_state *state)
> > +{
> > +	int ret;
> >  	struct intel_crtc *crtc;
> > -	const struct intel_crtc_state *crtc_state;
> > -	enum pipe pipe;
> > +	struct intel_crtc_state *new_crtc_state;
> > +	struct intel_bw_state *new_bw_state = NULL;
> > +	const struct intel_bw_state *old_bw_state = NULL;
> > +	int i;
> >  
> > -	if (!intel_has_sagv(dev_priv))
> > -		return false;
> > +	for_each_new_intel_crtc_in_state(state, crtc,
> > +					 new_crtc_state, i) {
> > +		new_bw_state = intel_atomic_get_bw_state(state);
> > +		if (IS_ERR(new_bw_state))
> > +			return PTR_ERR(new_bw_state);
> >  
> > -	/*
> > -	 * If there are no active CRTCs, no additional checks need be performed
> > -	 */
> > -	if (hweight8(state->active_pipes) == 0)
> > -		return true;
> > +		old_bw_state = intel_atomic_get_old_bw_state(state);
> >  
> > -	/*
> > -	 * SKL+ workaround: bspec recommends we disable SAGV when we have
> > -	 * more then one pipe enabled
> > -	 */
> > -	if (hweight8(state->active_pipes) > 1)
> > -		return false;
> > +		if (intel_crtc_can_enable_sagv(new_crtc_state))
> > +			new_bw_state->pipe_sagv_reject &= ~BIT(crtc->pipe);
> > +		else
> > +			new_bw_state->pipe_sagv_reject |= BIT(crtc->pipe);
> > +	}
> >  
> > -	/* Since we're now guaranteed to only have one active CRTC... */
> > -	pipe = ffs(state->active_pipes) - 1;
> > -	crtc = intel_get_crtc_for_pipe(dev_priv, pipe);
> > -	crtc_state = to_intel_crtc_state(crtc->base.state);
> > +	if (!new_bw_state)
> > +		return 0;
> >  
> > -	return intel_crtc_can_enable_sagv(crtc_state);
> > +	if (intel_can_enable_sagv(new_bw_state) != intel_can_enable_sagv(old_bw_state)) {
> > +		ret = intel_atomic_lock_global_state(&new_bw_state->base);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +
> > +	return 0;
> >  }
> >  
> >  /*
> > @@ -5860,6 +5911,12 @@ skl_compute_wm(struct intel_atomic_state *state)
> >  	if (ret)
> >  		return ret;
> >  
> > +	if (state->modeset) {
> > +		ret = intel_compute_sagv_mask(state);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +
> >  	/*
> >  	 * skl_compute_ddb() will have adjusted the final watermarks
> >  	 * based on how much ddb is available. Now we can actually
> > diff --git a/drivers/gpu/drm/i915/intel_pm.h b/drivers/gpu/drm/i915/intel_pm.h
> > index 9a6036ab0f90..fd1dc422e6c5 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.h
> > +++ b/drivers/gpu/drm/i915/intel_pm.h
> > @@ -9,6 +9,7 @@
> >  #include <linux/types.h>
> >  
> >  #include "i915_reg.h"
> > +#include "display/intel_bw.h"
> >  
> >  struct drm_device;
> >  struct drm_i915_private;
> > @@ -41,7 +42,7 @@ void skl_pipe_wm_get_hw_state(struct intel_crtc *crtc,
> >  			      struct skl_pipe_wm *out);
> >  void g4x_wm_sanitize(struct drm_i915_private *dev_priv);
> >  void vlv_wm_sanitize(struct drm_i915_private *dev_priv);
> > -bool intel_can_enable_sagv(struct intel_atomic_state *state);
> > +bool intel_can_enable_sagv(const struct intel_bw_state *bw_state);
> >  int intel_enable_sagv(struct drm_i915_private *dev_priv);
> >  int intel_disable_sagv(struct drm_i915_private *dev_priv);
> >  void intel_sagv_pre_plane_update(struct intel_atomic_state *state);
> > -- 
> > 2.24.1.485.gad05a3d8e5
> 
> -- 
> Ville Syrjälä
> Intel


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