[Intel-gfx] [PATCH 1/4] drm/i915: Stop forcing clock gating init for future platforms

[Lucas De Marchi]

On Wed, Sep 06, 2023 at 04:47:34PM -0700, Matt Roper wrote:
>In the early days of i915, pretty much every platform needed to
>initialize _something_ in the clock gating init functions.  In some
>cases the items initialized were inside the GT (and really should have
>been initialized through the GT workaround infrastructure instead).
>In other cases they were display programming (sometimes not even related
>to "clock gating" at all!) which probably needs to move inside the
>display-specific code.  The number of initialization tasks that are
>truly "clock gating" and don't fall within the GT or display domains is
>relatively limited.  Let's stop forcing future platforms to always
>define a clock gating init hook.
>
>Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
>---
> drivers/gpu/drm/i915/intel_clock_gating.c | 10 +++-------
> 1 file changed, 3 insertions(+), 7 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_clock_gating.c b/drivers/gpu/drm/i915/intel_clock_gating.c
>index c66eb6abd4a2..1f2e2d7087cb 100644
>--- a/drivers/gpu/drm/i915/intel_clock_gating.c
>+++ b/drivers/gpu/drm/i915/intel_clock_gating.c
>@@ -835,9 +835,7 @@ CG_FUNCS(nop);
>  */
> void intel_clock_gating_hooks_init(struct drm_i915_private *i915)
> {
>-	if (IS_METEORLAKE(i915))
>-		i915->clock_gating_funcs = &nop_clock_gating_funcs;
>-	else if (IS_PONTEVECCHIO(i915))
>+	if (IS_PONTEVECCHIO(i915))

shouldn't we use the normal "last platforms first" and just add a check
here for GRAPHICS/DISPLAY version >= x?

> 		i915->clock_gating_funcs = &pvc_clock_gating_funcs;
> 	else if (IS_DG2(i915))
> 		i915->clock_gating_funcs = &dg2_clock_gating_funcs;
>@@ -845,7 +843,7 @@ void intel_clock_gating_hooks_init(struct drm_i915_private *i915)
> 		i915->clock_gating_funcs = &xehpsdv_clock_gating_funcs;
> 	else if (IS_ALDERLAKE_P(i915))
> 		i915->clock_gating_funcs = &adlp_clock_gating_funcs;
>-	else if (GRAPHICS_VER(i915) == 12)
>+	else if (DISPLAY_VER(i915) == 12)

why changing this while the others still check for graphics version?

Lucas De Marchi

> 		i915->clock_gating_funcs = &gen12lp_clock_gating_funcs;
> 	else if (GRAPHICS_VER(i915) == 11)
> 		i915->clock_gating_funcs = &icl_clock_gating_funcs;
>@@ -885,8 +883,6 @@ void intel_clock_gating_hooks_init(struct drm_i915_private *i915)
> 		i915->clock_gating_funcs = &i85x_clock_gating_funcs;
> 	else if (GRAPHICS_VER(i915) == 2)
> 		i915->clock_gating_funcs = &i830_clock_gating_funcs;
>-	else {
>-		MISSING_CASE(INTEL_DEVID(i915));
>+	else
> 		i915->clock_gating_funcs = &nop_clock_gating_funcs;
>-	}
> }
>-- 
>2.41.0
>