drm/i915: Track minimum acceptable cdclk instead of "minimum dotclock"

Make the min_pixclk thing less confusing by changing it to track
the minimum acceptable cdclk frequency instead. This means moving
the application of the guardbands to a slightly higher level from
the low level platform specific calc_cdclk() functions.

The immediate benefit is elimination of the confusing 2x factors
on GLK/CNL+ in the audio workarounds (which stems from the fact
that the pipes produce two pixels per clock).

v2: Keep cdclk higher on CNL to workaround missing DDI clock voltage handling
v3: Squash with the CNL cdclk limits patch (DK)
v4: s/intel_min_cdclk/intel_pixel_rate_to_cdclk/ (DK)

Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170830185703.8189-1-ville.syrjala@linux.intel.com

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 469c06000774..b748cb4b30d6 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -384,7 +384,8 @@ struct intel_atomic_state {
 	unsigned int active_pipe_changes;
 
 	unsigned int active_crtcs;
-	unsigned int min_pixclk[I915_MAX_PIPES];
+	/* minimum acceptable cdclk for each pipe */
+	int min_cdclk[I915_MAX_PIPES];
 
 	struct intel_shared_dpll_state shared_dpll[I915_NUM_PLLS];
 
@@ -1290,6 +1291,7 @@ void intel_audio_init(struct drm_i915_private *dev_priv);
 void intel_audio_deinit(struct drm_i915_private *dev_priv);
 
 /* intel_cdclk.c */
+int intel_crtc_compute_min_cdclk(const struct intel_crtc_state *crtc_state);
 void skl_init_cdclk(struct drm_i915_private *dev_priv);
 void skl_uninit_cdclk(struct drm_i915_private *dev_priv);
 void cnl_init_cdclk(struct drm_i915_private *dev_priv);