drm/i915: Skip modeset for cdclk changes if possible

If we have only a single active pipe and the cdclk change only requires
the cd2x divider to be updated bxt+ can do the update with forcing a full
modeset on the pipe. Try to hook that up.

v2:
- Wait for vblank after an optimized CDCLK change.
- Avoid optimization if the pipe needs a modeset (or was disabled).
- Split CDCLK change to a pre/post plane update step.
v3:
- Use correct version of CDCLK state as old state. (Ville)
- Remove unused intel_cdclk_can_skip_modeset()
v4:
- For consistency call intel_set_cdclk_post_plane_update() only during
  modesets (and not fastsets).
v5:
- Remove the logic to update the CD2X divider on-the-fly on ICL, since
  only a divider of 1 is supported there. Clint also noticed that the
  pipe select bits in CDCLK_CTL are oddly defined on ICL, it's not clear
  yet whether that's only an error in the specification.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Abhay Kumar <abhay.kumar@intel.com>
Tested-by: Abhay Kumar <abhay.kumar@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Clint Taylor <Clinton.A.Taylor@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190327101321.3095-1-imre.deak@intel.com

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index bde4dae..8f38d03 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -282,7 +282,8 @@ struct drm_i915_display_funcs {
        void (*get_cdclk)(struct drm_i915_private *dev_priv,
                          struct intel_cdclk_state *cdclk_state);
        void (*set_cdclk)(struct drm_i915_private *dev_priv,
-                         const struct intel_cdclk_state *cdclk_state);
+                         const struct intel_cdclk_state *cdclk_state,
+                         enum pipe pipe);
        int (*get_fifo_size)(struct drm_i915_private *dev_priv,
                             enum i9xx_plane_id i9xx_plane);
        int (*compute_pipe_wm)(struct intel_crtc_state *cstate);

diff --git a/drivers/gpu/drm/i915/intel_cdclk.c b/drivers/gpu/drm/i915/intel_cdclk.c
index 2fc4434..b8cd481 100644 (file)
--- a/drivers/gpu/drm/i915/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/intel_cdclk.c
@@ -517,7 +517,8 @@ static void vlv_program_pfi_credits(struct drm_i915_private *dev_priv)
 }
 
 static void vlv_set_cdclk(struct drm_i915_private *dev_priv,
-                         const struct intel_cdclk_state *cdclk_state)
+                         const struct intel_cdclk_state *cdclk_state,
+                         enum pipe pipe)
 {
        int cdclk = cdclk_state->cdclk;
        u32 val, cmd = cdclk_state->voltage_level;
@@ -599,7 +600,8 @@ static void vlv_set_cdclk(struct drm_i915_private *dev_priv,
 }
 
 static void chv_set_cdclk(struct drm_i915_private *dev_priv,
-                         const struct intel_cdclk_state *cdclk_state)
+                         const struct intel_cdclk_state *cdclk_state,
+                         enum pipe pipe)
 {
        int cdclk = cdclk_state->cdclk;
        u32 val, cmd = cdclk_state->voltage_level;
@@ -698,7 +700,8 @@ static void bdw_get_cdclk(struct drm_i915_private *dev_priv,
 }
 
 static void bdw_set_cdclk(struct drm_i915_private *dev_priv,
-                         const struct intel_cdclk_state *cdclk_state)
+                         const struct intel_cdclk_state *cdclk_state,
+                         enum pipe pipe)
 {
        int cdclk = cdclk_state->cdclk;
        u32 val;
@@ -988,7 +991,8 @@ static void skl_dpll0_disable(struct drm_i915_private *dev_priv)
 }
 
 static void skl_set_cdclk(struct drm_i915_private *dev_priv,
-                         const struct intel_cdclk_state *cdclk_state)
+                         const struct intel_cdclk_state *cdclk_state,
+                         enum pipe pipe)
 {
        int cdclk = cdclk_state->cdclk;
        int vco = cdclk_state->vco;
@@ -1159,7 +1163,7 @@ void skl_init_cdclk(struct drm_i915_private *dev_priv)
        cdclk_state.cdclk = skl_calc_cdclk(0, cdclk_state.vco);
        cdclk_state.voltage_level = skl_calc_voltage_level(cdclk_state.cdclk);
 
-       skl_set_cdclk(dev_priv, &cdclk_state);
+       skl_set_cdclk(dev_priv, &cdclk_state, INVALID_PIPE);
 }
 
 /**
@@ -1177,7 +1181,7 @@ void skl_uninit_cdclk(struct drm_i915_private *dev_priv)
        cdclk_state.vco = 0;
        cdclk_state.voltage_level = skl_calc_voltage_level(cdclk_state.cdclk);
 
-       skl_set_cdclk(dev_priv, &cdclk_state);
+       skl_set_cdclk(dev_priv, &cdclk_state, INVALID_PIPE);
 }
 
 static int bxt_calc_cdclk(int min_cdclk)
@@ -1356,7 +1360,8 @@ static void bxt_de_pll_enable(struct drm_i915_private *dev_priv, int vco)
 }
 
 static void bxt_set_cdclk(struct drm_i915_private *dev_priv,
-                         const struct intel_cdclk_state *cdclk_state)
+                         const struct intel_cdclk_state *cdclk_state,
+                         enum pipe pipe)
 {
        int cdclk = cdclk_state->cdclk;
        int vco = cdclk_state->vco;
@@ -1409,11 +1414,10 @@ static void bxt_set_cdclk(struct drm_i915_private *dev_priv,
                bxt_de_pll_enable(dev_priv, vco);
 
        val = divider | skl_cdclk_decimal(cdclk);
-       /*
-        * 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;
+       if (pipe == INVALID_PIPE)
+               val |= BXT_CDCLK_CD2X_PIPE_NONE;
+       else
+               val |= BXT_CDCLK_CD2X_PIPE(pipe);
        /*
         * Disable SSA Precharge when CD clock frequency < 500 MHz,
         * enable otherwise.
@@ -1422,6 +1426,9 @@ static void bxt_set_cdclk(struct drm_i915_private *dev_priv,
                val |= BXT_CDCLK_SSA_PRECHARGE_ENABLE;
        I915_WRITE(CDCLK_CTL, val);
 
+       if (pipe != INVALID_PIPE)
+               intel_wait_for_vblank(dev_priv, pipe);
+
        mutex_lock(&dev_priv->pcu_lock);
        /*
         * The timeout isn't specified, the 2ms used here is based on
@@ -1526,7 +1533,7 @@ void bxt_init_cdclk(struct drm_i915_private *dev_priv)
        }
        cdclk_state.voltage_level = bxt_calc_voltage_level(cdclk_state.cdclk);
 
-       bxt_set_cdclk(dev_priv, &cdclk_state);
+       bxt_set_cdclk(dev_priv, &cdclk_state, INVALID_PIPE);
 }
 
 /**
@@ -1544,7 +1551,7 @@ void bxt_uninit_cdclk(struct drm_i915_private *dev_priv)
        cdclk_state.vco = 0;
        cdclk_state.voltage_level = bxt_calc_voltage_level(cdclk_state.cdclk);
 
-       bxt_set_cdclk(dev_priv, &cdclk_state);
+       bxt_set_cdclk(dev_priv, &cdclk_state, INVALID_PIPE);
 }
 
 static int cnl_calc_cdclk(int min_cdclk)
@@ -1664,7 +1671,8 @@ static void cnl_cdclk_pll_enable(struct drm_i915_private *dev_priv, int vco)
 }
 
 static void cnl_set_cdclk(struct drm_i915_private *dev_priv,
-                         const struct intel_cdclk_state *cdclk_state)
+                         const struct intel_cdclk_state *cdclk_state,
+                         enum pipe pipe)
 {
        int cdclk = cdclk_state->cdclk;
        int vco = cdclk_state->vco;
@@ -1705,13 +1713,15 @@ static void cnl_set_cdclk(struct drm_i915_private *dev_priv,
                cnl_cdclk_pll_enable(dev_priv, vco);
 
        val = divider | skl_cdclk_decimal(cdclk);
-       /*
-        * 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;
+       if (pipe == INVALID_PIPE)
+               val |= BXT_CDCLK_CD2X_PIPE_NONE;
+       else
+               val |= BXT_CDCLK_CD2X_PIPE(pipe);
        I915_WRITE(CDCLK_CTL, val);
 
+       if (pipe != INVALID_PIPE)
+               intel_wait_for_vblank(dev_priv, pipe);
+
        /* inform PCU of the change */
        mutex_lock(&dev_priv->pcu_lock);
        sandybridge_pcode_write(dev_priv, SKL_PCODE_CDCLK_CONTROL,
@@ -1848,7 +1858,8 @@ static int icl_calc_cdclk_pll_vco(struct drm_i915_private *dev_priv, int cdclk)
 }
 
 static void icl_set_cdclk(struct drm_i915_private *dev_priv,
-                         const struct intel_cdclk_state *cdclk_state)
+                         const struct intel_cdclk_state *cdclk_state,
+                         enum pipe pipe)
 {
        unsigned int cdclk = cdclk_state->cdclk;
        unsigned int vco = cdclk_state->vco;
@@ -1873,6 +1884,11 @@ static void icl_set_cdclk(struct drm_i915_private *dev_priv,
        if (dev_priv->cdclk.hw.vco != vco)
                cnl_cdclk_pll_enable(dev_priv, vco);
 
+       /*
+        * On ICL CD2X_DIV can only be 1, so we'll never end up changing the
+        * divider here synchronized to a pipe while CDCLK is on, nor will we
+        * need the corresponding vblank wait.
+        */
        I915_WRITE(CDCLK_CTL, ICL_CDCLK_CD2X_PIPE_NONE |
                              skl_cdclk_decimal(cdclk));
 
@@ -2003,7 +2019,7 @@ sanitize:
        sanitized_state.voltage_level =
                                icl_calc_voltage_level(sanitized_state.cdclk);
 
-       icl_set_cdclk(dev_priv, &sanitized_state);
+       icl_set_cdclk(dev_priv, &sanitized_state, INVALID_PIPE);
 }
 
 /**
@@ -2021,7 +2037,7 @@ void icl_uninit_cdclk(struct drm_i915_private *dev_priv)
        cdclk_state.vco = 0;
        cdclk_state.voltage_level = icl_calc_voltage_level(cdclk_state.cdclk);
 
-       icl_set_cdclk(dev_priv, &cdclk_state);
+       icl_set_cdclk(dev_priv, &cdclk_state, INVALID_PIPE);
 }
 
 /**
@@ -2049,7 +2065,7 @@ void cnl_init_cdclk(struct drm_i915_private *dev_priv)
        cdclk_state.vco = cnl_cdclk_pll_vco(dev_priv, cdclk_state.cdclk);
        cdclk_state.voltage_level = cnl_calc_voltage_level(cdclk_state.cdclk);
 
-       cnl_set_cdclk(dev_priv, &cdclk_state);
+       cnl_set_cdclk(dev_priv, &cdclk_state, INVALID_PIPE);
 }
 
 /**
@@ -2067,7 +2083,7 @@ void cnl_uninit_cdclk(struct drm_i915_private *dev_priv)
        cdclk_state.vco = 0;
        cdclk_state.voltage_level = cnl_calc_voltage_level(cdclk_state.cdclk);
 
-       cnl_set_cdclk(dev_priv, &cdclk_state);
+       cnl_set_cdclk(dev_priv, &cdclk_state, INVALID_PIPE);
 }
 
 /**
@@ -2087,6 +2103,27 @@ bool intel_cdclk_needs_modeset(const struct intel_cdclk_state *a,
 }
 
 /**
+ * intel_cdclk_needs_cd2x_update - Determine if two CDCLK states require a cd2x divider update
+ * @a: first CDCLK state
+ * @b: second CDCLK state
+ *
+ * Returns:
+ * True if the CDCLK states require just a cd2x divider update, false if not.
+ */
+bool intel_cdclk_needs_cd2x_update(struct drm_i915_private *dev_priv,
+                                  const struct intel_cdclk_state *a,
+                                  const struct intel_cdclk_state *b)
+{
+       /* Older hw doesn't have the capability */
+       if (INTEL_GEN(dev_priv) < 10 && !IS_GEN9_LP(dev_priv))
+               return false;
+
+       return a->cdclk != b->cdclk &&
+               a->vco == b->vco &&
+               a->ref == b->ref;
+}
+
+/**
  * intel_cdclk_changed - Determine if two CDCLK states are different
  * @a: first CDCLK state
  * @b: second CDCLK state
@@ -2134,12 +2171,14 @@ void intel_dump_cdclk_state(const struct intel_cdclk_state *cdclk_state,
  * intel_set_cdclk - Push the CDCLK state to the hardware
  * @dev_priv: i915 device
  * @cdclk_state: new CDCLK state
+ * @pipe: pipe with which to synchronize the update
  *
  * Program the hardware based on the passed in CDCLK state,
  * if necessary.
  */
-void intel_set_cdclk(struct drm_i915_private *dev_priv,
-                    const struct intel_cdclk_state *cdclk_state)
+static void intel_set_cdclk(struct drm_i915_private *dev_priv,
+                           const struct intel_cdclk_state *cdclk_state,
+                           enum pipe pipe)
 {
        if (!intel_cdclk_changed(&dev_priv->cdclk.hw, cdclk_state))
                return;
@@ -2149,7 +2188,7 @@ void intel_set_cdclk(struct drm_i915_private *dev_priv,
 
        intel_dump_cdclk_state(cdclk_state, "Changing CDCLK to");
 
-       dev_priv->display.set_cdclk(dev_priv, cdclk_state);
+       dev_priv->display.set_cdclk(dev_priv, cdclk_state, pipe);
 
        if (WARN(intel_cdclk_changed(&dev_priv->cdclk.hw, cdclk_state),
                 "cdclk state doesn't match!\n")) {
@@ -2158,6 +2197,46 @@ void intel_set_cdclk(struct drm_i915_private *dev_priv,
        }
 }
 
+/**
+ * intel_set_cdclk_pre_plane_update - Push the CDCLK state to the hardware
+ * @dev_priv: i915 device
+ * @old_state: old CDCLK state
+ * @new_state: new CDCLK state
+ * @pipe: pipe with which to synchronize the update
+ *
+ * Program the hardware before updating the HW plane state based on the passed
+ * in CDCLK state, if necessary.
+ */
+void
+intel_set_cdclk_pre_plane_update(struct drm_i915_private *dev_priv,
+                                const struct intel_cdclk_state *old_state,
+                                const struct intel_cdclk_state *new_state,
+                                enum pipe pipe)
+{
+       if (pipe == INVALID_PIPE || old_state->cdclk <= new_state->cdclk)
+               intel_set_cdclk(dev_priv, new_state, pipe);
+}
+
+/**
+ * intel_set_cdclk_post_plane_update - Push the CDCLK state to the hardware
+ * @dev_priv: i915 device
+ * @old_state: old CDCLK state
+ * @new_state: new CDCLK state
+ * @pipe: pipe with which to synchronize the update
+ *
+ * Program the hardware after updating the HW plane state based on the passed
+ * in CDCLK state, if necessary.
+ */
+void
+intel_set_cdclk_post_plane_update(struct drm_i915_private *dev_priv,
+                                 const struct intel_cdclk_state *old_state,
+                                 const struct intel_cdclk_state *new_state,
+                                 enum pipe pipe)
+{
+       if (pipe != INVALID_PIPE && old_state->cdclk > new_state->cdclk)
+               intel_set_cdclk(dev_priv, new_state, pipe);
+}
+
 static int intel_pixel_rate_to_cdclk(struct drm_i915_private *dev_priv,
                                     int pixel_rate)
 {

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 1a3d370..7ecfb7d 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13002,6 +13002,7 @@ static int intel_modeset_checks(struct drm_atomic_state *state)
        intel_state->active_crtcs = dev_priv->active_crtcs;
        intel_state->cdclk.logical = dev_priv->cdclk.logical;
        intel_state->cdclk.actual = dev_priv->cdclk.actual;
+       intel_state->cdclk.pipe = INVALID_PIPE;
 
        for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
                if (new_crtc_state->active)
@@ -13021,6 +13022,8 @@ static int intel_modeset_checks(struct drm_atomic_state *state)
         * adjusted_mode bits in the crtc directly.
         */
        if (dev_priv->display.modeset_calc_cdclk) {
+               enum pipe pipe;
+
                ret = dev_priv->display.modeset_calc_cdclk(state);
                if (ret < 0)
                        return ret;
@@ -13037,12 +13040,36 @@ static int intel_modeset_checks(struct drm_atomic_state *state)
                                return ret;
                }
 
+               if (is_power_of_2(intel_state->active_crtcs)) {
+                       struct drm_crtc *crtc;
+                       struct drm_crtc_state *crtc_state;
+
+                       pipe = ilog2(intel_state->active_crtcs);
+                       crtc = &intel_get_crtc_for_pipe(dev_priv, pipe)->base;
+                       crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
+                       if (crtc_state && needs_modeset(crtc_state))
+                               pipe = INVALID_PIPE;
+               } else {
+                       pipe = INVALID_PIPE;
+               }
+
                /* All pipes must be switched off while we change the cdclk. */
-               if (intel_cdclk_needs_modeset(&dev_priv->cdclk.actual,
-                                             &intel_state->cdclk.actual)) {
+               if (pipe != INVALID_PIPE &&
+                   intel_cdclk_needs_cd2x_update(dev_priv,
+                                                 &dev_priv->cdclk.actual,
+                                                 &intel_state->cdclk.actual)) {
+                       ret = intel_lock_all_pipes(state);
+                       if (ret < 0)
+                               return ret;
+
+                       intel_state->cdclk.pipe = pipe;
+               } else if (intel_cdclk_needs_modeset(&dev_priv->cdclk.actual,
+                                                    &intel_state->cdclk.actual)) {
                        ret = intel_modeset_all_pipes(state);
                        if (ret < 0)
                                return ret;
+
+                       intel_state->cdclk.pipe = INVALID_PIPE;
                }
 
                DRM_DEBUG_KMS("New cdclk calculated to be logical %u kHz, actual %u kHz\n",
@@ -13451,7 +13478,10 @@ static void intel_atomic_commit_tail(struct drm_atomic_state *state)
        if (intel_state->modeset) {
                drm_atomic_helper_update_legacy_modeset_state(state->dev, state);
 
-               intel_set_cdclk(dev_priv, &dev_priv->cdclk.actual);
+               intel_set_cdclk_pre_plane_update(dev_priv,
+                                                &intel_state->cdclk.actual,
+                                                &dev_priv->cdclk.actual,
+                                                intel_state->cdclk.pipe);
 
                /*
                 * SKL workaround: bspec recommends we disable the SAGV when we
@@ -13480,6 +13510,12 @@ static void intel_atomic_commit_tail(struct drm_atomic_state *state)
        /* Now enable the clocks, plane, pipe, and connectors that we set up. */
        dev_priv->display.update_crtcs(state);
 
+       if (intel_state->modeset)
+               intel_set_cdclk_post_plane_update(dev_priv,
+                                                 &intel_state->cdclk.actual,
+                                                 &dev_priv->cdclk.actual,
+                                                 intel_state->cdclk.pipe);
+
        /* FIXME: We should call drm_atomic_helper_commit_hw_done() here
         * already, but still need the state for the delayed optimization. To
         * fix this:

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 4dbe123..6454461 100644 (file)
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -559,6 +559,8 @@ struct intel_atomic_state {
 
                int force_min_cdclk;
                bool force_min_cdclk_changed;
+               /* pipe to which cd2x update is synchronized */
+               enum pipe pipe;
        } cdclk;
 
        bool dpll_set, modeset;
@@ -1694,13 +1696,24 @@ void intel_init_cdclk_hooks(struct drm_i915_private *dev_priv);
 void intel_update_max_cdclk(struct drm_i915_private *dev_priv);
 void intel_update_cdclk(struct drm_i915_private *dev_priv);
 void intel_update_rawclk(struct drm_i915_private *dev_priv);
+bool intel_cdclk_needs_cd2x_update(struct drm_i915_private *dev_priv,
+                                  const struct intel_cdclk_state *a,
+                                  const struct intel_cdclk_state *b);
 bool intel_cdclk_needs_modeset(const struct intel_cdclk_state *a,
                               const struct intel_cdclk_state *b);
 bool intel_cdclk_changed(const struct intel_cdclk_state *a,
                         const struct intel_cdclk_state *b);
 void intel_cdclk_swap_state(struct intel_atomic_state *state);
-void intel_set_cdclk(struct drm_i915_private *dev_priv,
-                    const struct intel_cdclk_state *cdclk_state);
+void
+intel_set_cdclk_pre_plane_update(struct drm_i915_private *dev_priv,
+                                const struct intel_cdclk_state *old_state,
+                                const struct intel_cdclk_state *new_state,
+                                enum pipe pipe);
+void
+intel_set_cdclk_post_plane_update(struct drm_i915_private *dev_priv,
+                                 const struct intel_cdclk_state *old_state,
+                                 const struct intel_cdclk_state *new_state,
+                                 enum pipe pipe);
 void intel_dump_cdclk_state(const struct intel_cdclk_state *cdclk_state,
                            const char *context);