Re: [Intel-gfx] [PATCH V6] drm/i915/gen11: Disable cursor clock gating in HDR mode

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, Sep 27, 2021 at 03:32:40PM +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 V5:
> 	- replace intel_de_read with intel_de_rmw - Jani
> Changes since V4:
>         - Added WA needed check - Ville
>         - Replace BIT with REG_BIT - Ville
>         - Add WA enable/disable support back which was added in V1 - Ville
> 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
> 
> Signed-off-by: Tejas Upadhyay <tejaskumarx.surendrakumar.upadhyay@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 31 ++++++++++++++++++++
>  drivers/gpu/drm/i915/i915_reg.h              |  1 +
>  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 f27c294beb92..e6ccc986bf27 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -214,6 +214,14 @@ 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(struct drm_i915_private *dev_priv, enum pipe pipe,
> +		       bool enable)
> +{
> +	intel_de_rmw(dev_priv, CLKGATE_DIS_PSL(pipe), CURSOR_GATING_DIS, enable ? CURSOR_GATING_DIS : 0);

Checkapatch complained about the long line. Trivial to fix here.

> +}
> +
>  static bool
>  is_trans_port_sync_slave(const struct intel_crtc_state *crtc_state)
>  {
> @@ -2356,6 +2364,19 @@ static bool needs_scalerclk_wa(const struct intel_crtc_state *crtc_state)
>  	return false;
>  }
>  
> +static bool needs_cursorclk_wa(const struct intel_crtc_state *crtc_state)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
> +
> +	/* Wa_1604331009:icl,jsl,ehl */
> +	if (is_hdr_mode(crtc_state) &&
> +	    crtc_state->active_planes & BIT(PLANE_CURSOR) &&
> +	    DISPLAY_VER(dev_priv) == 11)
> +		return true;
> +
> +	return false;
> +}
> +
>  static bool planes_enabling(const struct intel_crtc_state *old_crtc_state,
>  			    const struct intel_crtc_state *new_crtc_state)
>  {
> @@ -2398,6 +2419,11 @@ static void intel_post_plane_update(struct intel_atomic_state *state,
>  	if (needs_scalerclk_wa(old_crtc_state) &&
>  	    !needs_scalerclk_wa(new_crtc_state))
>  		icl_wa_scalerclkgating(dev_priv, pipe, false);
> +
> +	if (needs_cursorclk_wa(old_crtc_state) &&
> +	    !needs_cursorclk_wa(new_crtc_state))
> +		icl_wa_cursorclkgating(dev_priv, pipe, false);
> +

Stray newline.

>  }
>  
>  static void intel_crtc_enable_flip_done(struct intel_atomic_state *state,
> @@ -2494,6 +2520,11 @@ 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 */
> +	if (!needs_cursorclk_wa(old_crtc_state) &&
> +	    needs_cursorclk_wa(new_crtc_state))
> +		icl_wa_cursorclkgating(dev_priv, pipe, true);
> +
>  	/*
>  	 * 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 ef594df039db..7b3eed5b4e42 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -4272,6 +4272,7 @@ enum {
>  #define   DPF_GATING_DIS		(1 << 10)
>  #define   DPF_RAM_GATING_DIS		(1 << 9)
>  #define   DPFR_GATING_DIS		(1 << 8)
> +#define   CURSOR_GATING_DIS		REG_BIT(28)

Please keep the bits in order.

Otherwise lgtm
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

>  
>  #define CLKGATE_DIS_PSL(pipe) \
>  	_MMIO_PIPE(pipe, _CLKGATE_DIS_PSL_A, _CLKGATE_DIS_PSL_B)
> -- 
> 2.31.1

-- 
Ville Syrjälä
Intel