Re: [Intel-gfx] [PATCH 01/10] drm/i915: Remove PLL asserts from .load_luts()

[Jani Nikula <jani.nikula@linux.intel.com>]

On Thu, 29 Sep 2022, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> .load_luts() potentially runs from the vblank worker, and is
> under a deadline to complete within the vblank. Thus we can't
> do expesive stuff like talk to the Punit, etc.
>
> To that end get rid of the assert_dsi_pll_enabled() call for
> vlv/chv. We'll just have to trust that the PLL is already enabled
> here.
>
> And I don't think the normal assert_pll_enabled() really buys us
> anything useful on gmch platforms either, so nuke that one too.
> We don't have corresponding asserts in the ilk+ codepaths anyway
> despite the hardware (IIRC) still requiring the clock to be
> enabled when we access the LUT.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Acked-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_color.c | 11 -----------
>  1 file changed, 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_color.c b/drivers/gpu/drm/i915/display/intel_color.c
> index 6bda4274eae9..bbc56affb3ec 100644
> --- a/drivers/gpu/drm/i915/display/intel_color.c
> +++ b/drivers/gpu/drm/i915/display/intel_color.c
> @@ -25,9 +25,7 @@
>  #include "intel_color.h"
>  #include "intel_de.h"
>  #include "intel_display_types.h"
> -#include "intel_dpll.h"
>  #include "intel_dsb.h"
> -#include "vlv_dsi_pll.h"
>  
>  struct intel_color_funcs {
>  	int (*color_check)(struct intel_crtc_state *crtc_state);
> @@ -580,11 +578,8 @@ static void i9xx_load_lut_8(struct intel_crtc *crtc,
>  static void i9xx_load_luts(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);
>  	const struct drm_property_blob *gamma_lut = crtc_state->hw.gamma_lut;
>  
> -	assert_pll_enabled(dev_priv, crtc->pipe);
> -
>  	i9xx_load_lut_8(crtc, gamma_lut);
>  }
>  
> @@ -611,14 +606,8 @@ static void i965_load_lut_10p6(struct intel_crtc *crtc,
>  static void i965_load_luts(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);
>  	const struct drm_property_blob *gamma_lut = crtc_state->hw.gamma_lut;
>  
> -	if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DSI))
> -		assert_dsi_pll_enabled(dev_priv);
> -	else
> -		assert_pll_enabled(dev_priv, crtc->pipe);
> -
>  	if (crtc_state->gamma_mode == GAMMA_MODE_MODE_8BIT)
>  		i9xx_load_lut_8(crtc, gamma_lut);
>  	else

-- 
Jani Nikula, Intel Open Source Graphics Center