drm/i915: Bump CHV PFI credits to 63 when cdclk>=czclk

Switch from using 31 PFI credits to 63 PFI credits when cdclk>=czclk on
CHV. The spec lists both 31 and 63 as "suggested" values, but based on
feedback from hardware folks we should actually be using 63. Originally
I picked the 31 basically by flipping a coin.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Clint Taylor <Clinton.A.Taylor@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index c4ccc376ae44e122b379d99b67343cbbb8d41cf9..193ba79e5a41f138e87c5a1398439a1912aa6ca5 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6055,7 +6055,7 @@ static void vlv_program_pfi_credits(struct drm_i915_private *dev_priv)
        if (DIV_ROUND_CLOSEST(dev_priv->cdclk_freq, 1000) >= dev_priv->rps.cz_freq) {
                /* CHV suggested value is 31 or 63 */
                if (IS_CHERRYVIEW(dev_priv))
-                       credits = PFI_CREDIT_31;
+                       credits = PFI_CREDIT_63;
                else
                        credits = PFI_CREDIT(15);
        } else {