drm/i915: Program BXT_CDCLK_CD2X_PIPE
BXT could change the CD2X divider synchronized with a single pipe.
So assuming the DE PLL frequency doesn't need to be changed, we could
change cdclk without shutting off the pipe (when only a single pipe is
enabled). In the meantime let's configure CDCLK_CTL for non-double
buffered CD2X update, although it shouldn't really matter as long as
the selected pipe is disabled when reprogramming the divider.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462995892-32416-13-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com>
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 54ce0b1..86fbf72 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -7566,14 +7566,15 @@
#define CDCLK_FREQ_540 (1<<26)
#define CDCLK_FREQ_337_308 (2<<26)
#define CDCLK_FREQ_675_617 (3<<26)
-#define CDCLK_FREQ_DECIMAL_MASK (0x7ff)
-
#define BXT_CDCLK_CD2X_DIV_SEL_MASK (3<<22)
#define BXT_CDCLK_CD2X_DIV_SEL_1 (0<<22)
#define BXT_CDCLK_CD2X_DIV_SEL_1_5 (1<<22)
#define BXT_CDCLK_CD2X_DIV_SEL_2 (2<<22)
#define BXT_CDCLK_CD2X_DIV_SEL_4 (3<<22)
+#define BXT_CDCLK_CD2X_PIPE(pipe) ((pipe)<<20)
+#define BXT_CDCLK_CD2X_PIPE_NONE BXT_CDCLK_CD2X_PIPE(3)
#define BXT_CDCLK_SSA_PRECHARGE_ENABLE (1<<16)
+#define CDCLK_FREQ_DECIMAL_MASK (0x7ff)
/* LCPLL_CTL */
#define LCPLL1_CTL _MMIO(0x46010)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 176d23f..1e5bfe8 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5430,6 +5430,11 @@
DRM_ERROR("timeout waiting for DE PLL lock\n");
val = I915_READ(CDCLK_CTL);
+ /*
+ * FIXME if only the cd2x divider needs changing, it could be done
+ * without shutting off the pipe (if only one pipe is active).
+ */
+ val |= BXT_CDCLK_CD2X_PIPE_NONE;
val &= ~BXT_CDCLK_CD2X_DIV_SEL_MASK;
val |= divider;
/*