Re: [PATCH v2 08/16] drm/i915: Split watermark programming into pre and post steps

[Daniel Vetter <daniel@ffwll.ch>]

On Tue, Jun 03, 2014 at 05:51:01PM -0300, Paulo Zanoni wrote:
> 2014-05-22 11:48 GMT-03:00  <ville.syrjala@linux.intel.com>:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > We need to perform watermark programming before and after changing the
> > plane configuration. Add two new vfuncs to do that. The pre phase is
> > supposed to switch over to the intermediate watermarks which are
> > computed so that they can deal with both the old and new plane
> > configurations. The post phase will arm the vblank based update
> > systems to switch over to the optimal target watermarks after the
> > plane configuration has for sure changed.
> >
> > v2: Pass around intel_crtc and s/intel_crtc/crtc/
> >
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_drv.h  |  5 +++
> >  drivers/gpu/drm/i915/intel_drv.h | 11 +++++
> >  drivers/gpu/drm/i915/intel_pm.c  | 88 ++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 104 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> > index c90d5ac..d4f8ae8 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -407,6 +407,7 @@ struct intel_plane_config;
> >  struct intel_crtc;
> >  struct intel_limit;
> >  struct dpll;
> > +struct intel_crtc_wm_config;
> >
> >  struct drm_i915_display_funcs {
> >         bool (*fbc_enabled)(struct drm_device *dev);
> > @@ -437,6 +438,10 @@ struct drm_i915_display_funcs {
> >                                  struct drm_crtc *crtc,
> >                                  uint32_t sprite_width, int pixel_size,
> >                                  bool enable, bool scaled);
> > +       void (*program_wm_pre)(struct intel_crtc *crtc,
> > +                              const struct intel_crtc_wm_config *config);
> > +       void (*program_wm_post)(struct intel_crtc *crtc,
> > +                               const struct intel_crtc_wm_config *config);
> >         void (*modeset_global_resources)(struct drm_device *dev);
> >         /* Returns the active state of the crtc, and if the crtc is active,
> >          * fills out the pipe-config with the hw state. */
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > index 72f01b1..4b59be3 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -358,6 +358,13 @@ struct intel_pipe_wm {
> >         bool sprites_scaled;
> >  };
> >
> > +struct intel_crtc_wm_config {
> > +       /* target watermarks for the pipe */
> > +       struct intel_pipe_wm target;
> > +       /* intermediate watermarks for pending/active->target transition */
> > +       struct intel_pipe_wm intm;
> 
> It seems you always prefer shorter names such as "intm", and I usually
> prefer the longer ones like "intermediate". Looks like this is a
> common topic for my bikesheddings on your patches. When I read "intm"
> my brain parses it as "Int M" and then aborts execution =P

I agree with Paulo here. Some other name suggestion (since intermediate is
so long): transition/transit, merged, pending, ...
-Daniel

> 
> With or without that changed: Reviewed-by: Paulo Zanoni
> <paulo.r.zanoni@intel.com>
> 
> > +};
> > +
> >  struct intel_crtc {
> >         struct drm_crtc base;
> >         enum pipe pipe;
> > @@ -1001,6 +1008,10 @@ void intel_init_runtime_pm(struct drm_i915_private *dev_priv);
> >  void intel_fini_runtime_pm(struct drm_i915_private *dev_priv);
> >  void ilk_wm_get_hw_state(struct drm_device *dev);
> >  void ilk_update_pipe_wm(struct drm_device *dev, enum pipe pipe);
> > +void intel_program_watermarks_pre(struct intel_crtc *crtc,
> > +                                 const struct intel_crtc_wm_config *config);
> > +void intel_program_watermarks_post(struct intel_crtc *crtc,
> > +                                  const struct intel_crtc_wm_config *config);
> >
> >
> >  /* intel_sdvo.c */
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > index 6fc6416..ccf920a 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -2950,6 +2950,20 @@ void ilk_update_pipe_wm(struct drm_device *dev, enum pipe pipe)
> >         spin_unlock(&crtc->wm.lock);
> >  }
> >
> > +static void ilk_wm_cancel(struct intel_crtc *crtc)
> > +{
> > +       struct drm_device *dev = crtc->base.dev;
> > +
> > +       assert_spin_locked(&crtc->wm.lock);
> > +
> > +       crtc->wm.dirty = false;
> > +
> > +       if (crtc->wm.vblank) {
> > +               drm_vblank_put(dev, crtc->pipe);
> > +               crtc->wm.vblank = false;
> > +       }
> > +}
> > +
> >  static void ilk_update_sprite_wm(struct drm_plane *plane,
> >                                      struct drm_crtc *crtc,
> >                                      uint32_t sprite_width, int pixel_size,
> > @@ -3084,6 +3098,24 @@ void intel_update_sprite_watermarks(struct drm_plane *plane,
> >                                                    pixel_size, enabled, scaled);
> >  }
> >
> > +void intel_program_watermarks_pre(struct intel_crtc *crtc,
> > +                                 const struct intel_crtc_wm_config *config)
> > +{
> > +       struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
> > +
> > +       if (dev_priv->display.program_wm_pre)
> > +               dev_priv->display.program_wm_pre(crtc, config);
> > +}
> > +
> > +void intel_program_watermarks_post(struct intel_crtc *crtc,
> > +                                  const struct intel_crtc_wm_config *config)
> > +{
> > +       struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
> > +
> > +       if (dev_priv->display.program_wm_post)
> > +               dev_priv->display.program_wm_post(crtc, config);
> > +}
> > +
> >  static struct drm_i915_gem_object *
> >  intel_alloc_context_page(struct drm_device *dev)
> >  {
> > @@ -6522,6 +6554,60 @@ void intel_fini_runtime_pm(struct drm_i915_private *dev_priv)
> >         pm_runtime_disable(device);
> >  }
> >
> > +static void ilk_program_wm_pre(struct intel_crtc *crtc,
> > +                              const struct intel_crtc_wm_config *config)
> > +{
> > +       struct drm_device *dev = crtc->base.dev;
> > +       struct drm_i915_private *dev_priv = dev->dev_private;
> > +
> > +       mutex_lock(&dev_priv->wm.mutex);
> > +
> > +       spin_lock_irq(&crtc->wm.lock);
> > +       ilk_wm_cancel(crtc);
> > +       spin_unlock_irq(&crtc->wm.lock);
> > +
> > +       /* pending update (if any) got cancelled */
> > +       crtc->wm.pending = crtc->wm.active;
> > +
> > +       if (!memcmp(&crtc->wm.active, &config->intm, sizeof(config->intm)))
> > +               goto unlock;
> > +
> > +       crtc->wm.active = config->intm;
> > +
> > +       /* use the most up to date watermarks for other pipes */
> > +       ilk_refresh_pending_watermarks(dev);
> > +
> > +       /* switch over to the intermediate watermarks */
> > +       ilk_program_watermarks(dev);
> > +
> > + unlock:
> > +       mutex_unlock(&dev_priv->wm.mutex);
> > +}
> > +
> > +static void ilk_program_wm_post(struct intel_crtc *crtc,
> > +                               const struct intel_crtc_wm_config *config)
> > +{
> > +       struct drm_device *dev = crtc->base.dev;
> > +       struct drm_i915_private *dev_priv = dev->dev_private;
> > +       u32 vbl_count;
> > +
> > +       /*
> > +        * FIXME sample this inside the atomic section to avoid
> > +        * needlessly long periods w/ sub-par watermarks
> > +        */
> > +       vbl_count = dev->driver->get_vblank_counter(dev, crtc->pipe);
> > +
> > +       mutex_lock(&dev_priv->wm.mutex);
> > +
> > +       /*
> > +        * We can switch over to the target
> > +        * watermarks after the next vblank.
> > +        */
> > +       ilk_setup_pending_watermarks(crtc, &config->target, vbl_count);
> > +
> > +       mutex_unlock(&dev_priv->wm.mutex);
> > +}
> > +
> >  /* Set up chip specific power management-related functions */
> >  void intel_init_pm(struct drm_device *dev)
> >  {
> > @@ -6569,6 +6655,8 @@ void intel_init_pm(struct drm_device *dev)
> >                      dev_priv->wm.spr_latency[0] && dev_priv->wm.cur_latency[0])) {
> >                         dev_priv->display.update_wm = ilk_update_wm;
> >                         dev_priv->display.update_sprite_wm = ilk_update_sprite_wm;
> > +                       dev_priv->display.program_wm_pre = ilk_program_wm_pre;
> > +                       dev_priv->display.program_wm_post = ilk_program_wm_post;
> >                 } else {
> >                         DRM_DEBUG_KMS("Failed to read display plane latency. "
> >                                       "Disable CxSR\n");
> > --
> > 1.8.5.5
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> 
> 
> -- 
> Paulo Zanoni
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch