[PATCH v2 1/2] drm/i915/display: Add own counter for Panel Replay vblank workaround

[Hogander, Jouni]

On Wed, 2024-10-09 at 17:15 +0300, Jani Nikula wrote:
> On Wed, 09 Oct 2024, Jouni Högander <jouni.hogander at intel.com> wrote:
> > We are about to change meaning of vblank_enabled to fix Panel
> > Replay vblank
> > workaround. For sake of clarity we need to rename it.
> > Vblank_enabled is
> > used for i915gm/i945gm vblank irq workaround as well -> instead of
> > rename
> > add new counter named as vblank_wa_pipes.
> > 
> > v2:
> >   - s/vblank_wa_pipes/vblank_wa_num_pipes/
> >   - use int as a type for the counter
> > 
> > Signed-off-by: Jouni Högander <jouni.hogander at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_display_core.h | 2 ++
> >  drivers/gpu/drm/i915/display/intel_display_irq.c  | 8 ++++----
> >  2 files changed, 6 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_core.h
> > b/drivers/gpu/drm/i915/display/intel_display_core.h
> > index 982dd9469195..45697af25fa9 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_core.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_core.h
> > @@ -455,6 +455,8 @@ struct intel_display {
> >                 /* For i915gm/i945gm vblank irq workaround */
> >                 u8 vblank_enabled;
> 
> Maybe we want to rename this one too?

I tried to explain it in commit message. Seems I didn't succeed in it.

vblank_enabled is currently used by two workarounds:

1. i915gm/i945gm vblank irq workaround
2. LNL Panel Replay vblank workaround

1. and 2. are currently using vblank_enabled in a way they are
respecting it's meaning: is vblank enabled/disabled.

It was found out that 2. as it is implemented currently doesn't work
properly. Instead of information on vblank enabled/disabled we need to
know if there are pipes that need the workaround.

Renaming vblank_enabled wouldn't reflect how it's used in 1. This is
why I decided to add own variable for 2. and this is what this patch is
about: Keep vblank_enabled as it is for 1. and add own variable for 2.

BR,

Jouni Högander
 
> 
> BR,
> Jani.
> 
> >  
> > +               int vblank_wa_num_pipes;
> > +
> >                 struct work_struct vblank_dc_work;
> >  
> >                 u32 de_irq_mask[I915_MAX_PIPES];
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_irq.c
> > b/drivers/gpu/drm/i915/display/intel_display_irq.c
> > index a4367ddc7a44..8226ea218d77 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_irq.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display_irq.c
> > @@ -1424,7 +1424,7 @@ static void
> > intel_display_vblank_dc_work(struct work_struct *work)
> >         struct intel_display *display =
> >                 container_of(work, typeof(*display),
> > irq.vblank_dc_work);
> >         struct drm_i915_private *i915 = to_i915(display->drm);
> > -       u8 vblank_enabled = READ_ONCE(display->irq.vblank_enabled);
> > +       int vblank_wa_num_pipes = READ_ONCE(display-
> > >irq.vblank_wa_num_pipes);
> >  
> >         /*
> >          * NOTE: intel_display_power_set_target_dc_state is used
> > only by PSR
> > @@ -1432,7 +1432,7 @@ static void
> > intel_display_vblank_dc_work(struct work_struct *work)
> >          * PSR code. If DC3CO is taken into use we need take that
> > into account
> >          * here as well.
> >          */
> > -       intel_display_power_set_target_dc_state(i915,
> > vblank_enabled ? DC_STATE_DISABLE :
> > +       intel_display_power_set_target_dc_state(i915,
> > vblank_wa_num_pipes ? DC_STATE_DISABLE :
> >                                                 DC_STATE_EN_UPTO_DC
> > 6);
> >  }
> >  
> > @@ -1447,7 +1447,7 @@ int bdw_enable_vblank(struct drm_crtc *_crtc)
> >         if (gen11_dsi_configure_te(crtc, true))
> >                 return 0;
> >  
> > -       if (display->irq.vblank_enabled++ == 0 && crtc-
> > >block_dc_for_vblank)
> > +       if (display->irq.vblank_wa_num_pipes++ == 0 && crtc-
> > >block_dc_for_vblank)
> >                 schedule_work(&display->irq.vblank_dc_work);
> >  
> >         spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
> > @@ -1478,7 +1478,7 @@ void bdw_disable_vblank(struct drm_crtc
> > *_crtc)
> >         bdw_disable_pipe_irq(dev_priv, pipe, GEN8_PIPE_VBLANK);
> >         spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> >  
> > -       if (--display->irq.vblank_enabled == 0 && crtc-
> > >block_dc_for_vblank)
> > +       if (--display->irq.vblank_wa_num_pipes == 0 && crtc-
> > >block_dc_for_vblank)
> >                 schedule_work(&display->irq.vblank_dc_work);
> >  }
>