Re: [Intel-gfx] [PATCH V4] drm/i915/gen11: Disable cursor clock gating in HDR mode

["Surendrakumar Upadhyay, TejaskumarX" <tejaskumarx.surendrakumar.upadhyay@intel.com>]

> -----Original Message-----
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Sent: 01 September 2021 19:19
> To: Surendrakumar Upadhyay, TejaskumarX
> <tejaskumarx.surendrakumar.upadhyay@intel.com>
> Cc: intel-gfx@lists.freedesktop.org
> Subject: Re: [Intel-gfx] [PATCH V4] drm/i915/gen11: Disable cursor clock
> gating in HDR mode
> 
> On Tue, Jun 22, 2021 at 03:04:24PM +0530, Tejas Upadhyay wrote:
> > Display underrun in HDR mode when cursor is enabled.
> > RTL fix will be implemented CLKGATE_DIS_PSL_A bit 28-46520h.
> > As per W/A 1604331009, Disable cursor clock gating in HDR mode.
> >
> > Bspec : 33451
> >
> > Changes since V3:
> > 	- Disable WA when not in HDR mode or cursor plane not active - Ville
> > 	- Extract required args from crtc_state - Ville
> > 	- Create HDR mode API using bdw_set_pipemisc ref - Ville
> > 	- Tested with HDR video as well full setmode, WA applies and
> disables
> > Changes since V2:
> >         - Made it general gen11 WA
> >         - Removed WA needed check
> >         - Added cursor plane active check
> >         - Once WA enable, software will not disable Changes since V1:
> >         - Modified way CLKGATE_DIS_PSL bit 28 was modified
> >
> > Cc: Souza Jose <jose.souza@intel.com>
> > Signed-off-by: Tejas Upadhyay
> > <tejaskumarx.surendrakumar.upadhyay@intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_display.c | 27 ++++++++++++++++++++
> >  drivers/gpu/drm/i915/i915_reg.h              |  5 ++++
> >  2 files changed, 32 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_display.c
> > b/drivers/gpu/drm/i915/display/intel_display.c
> > index 6be1b31af07b..e1ea03b918df 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > @@ -358,6 +358,13 @@ static void intel_update_czclk(struct
> drm_i915_private *dev_priv)
> >  		dev_priv->czclk_freq);
> >  }
> >
> > +static bool
> > +is_hdr_mode(const struct intel_crtc_state *crtc_state) {
> > +	return (crtc_state->active_planes & ~(icl_hdr_plane_mask() |
> > +		BIT(PLANE_CURSOR))) == 0;
> > +}
> 
> Please use this in bdw_set_pipemisc() as well. This could be a separate prep
> patch actually.
> 
> > +
> >  /* WA Display #0827: Gen9:all */
> >  static void
> >  skl_wa_827(struct drm_i915_private *dev_priv, enum pipe pipe, bool
> > enable) @@ -383,6 +390,23 @@ icl_wa_scalerclkgating(struct
> drm_i915_private *dev_priv, enum pipe pipe,
> >  		               intel_de_read(dev_priv, CLKGATE_DIS_PSL(pipe)) &
> > ~DPFR_GATING_DIS);  }
> >
> > +/* Wa_1604331009:icl,jsl,ehl */
> > +	static void
> > +icl_wa_cursorclkgating(const struct intel_crtc_state *crtc_state) {
> > +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> > +	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> > +
> > +	if (is_hdr_mode(crtc_state) &&
> > +	    crtc_state->active_planes & BIT(PLANE_CURSOR) &&
> > +	    IS_GEN(dev_priv, 11))
> > +		intel_de_rmw(dev_priv, CLKGATE_DIS_PSL(crtc->pipe),
> > +			     CURSOR_GATING_DIS, CURSOR_GATING_DIS);
> > +	else
> > +		intel_de_rmw(dev_priv, CLKGATE_DIS_PSL(crtc->pipe),
> > +			     CURSOR_GATING_DIS, 0);
> > +}
> > +
> >  static bool
> >  is_trans_port_sync_slave(const struct intel_crtc_state *crtc_state)
> > { @@ -2939,6 +2963,9 @@ static void intel_pre_plane_update(struct
> > intel_atomic_state *state,
> >  	    needs_scalerclk_wa(new_crtc_state))
> >  		icl_wa_scalerclkgating(dev_priv, pipe, true);
> >
> > +	/* Wa_1604331009:icl,jsl,ehl */
> > +	icl_wa_cursorclkgating(new_crtc_state);
> 
> This looks a bit wrong. We shouldn't turn the clock gating back on until after
> HDR mode has been disabled.
> 
> So please model this after skl_wa_827() and icl_wa_scalerclkgating() so that
> a) the ordering is correct, and b) the code between all three w/as looks
> consistent.

I did not get what you are suggesting here. Can you please put psudo? Currently as far as I see icl_wa_cursorclkgating is already modelled  after skl_wa_827() and icl_wa_scalerclkgating(). Are referring same 
Or something else?

Thanks,
Tejas
> 
> > +
> >  	/*
> >  	 * Vblank time updates from the shadow to live plane control register
> >  	 * are blocked if the memory self-refresh mode is active at that
> > diff --git a/drivers/gpu/drm/i915/i915_reg.h
> > b/drivers/gpu/drm/i915/i915_reg.h index c857fafb8a30..703d708c773e
> > 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -4235,6 +4235,11 @@ enum {
> >  #define INF_UNIT_LEVEL_CLKGATE		_MMIO(0x9560)
> >  #define   CGPSF_CLKGATE_DIS		(1 << 3)
> >
> > +/*
> > + * GEN11 clock gating regs
> > + */
> > +#define   CURSOR_GATING_DIS            BIT(28)
> 
> This looks misplaced. It should be next to the other bits of whatever register
> this is. Also pls use REG_BIT() instead of BIT().
> 
> > +
> >  /*
> >   * Display engine regs
> >   */
> > --
> > 2.31.1
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> --
> Ville Syrjälä
> Intel