[PATCH 5.1 stable] drm/i915: Force 2*96 MHz cdclk on glk/cnl when audio power is enabled

[PATCH 5.1 stable] drm/i915: Force 2*96 MHz cdclk on glk/cnl when audio power is enabled

[Jian-Hong Pan]

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

commit 905801fe72377b4dc53c6e13eea1a91c6a4aa0c4 upstream.

CDCLK has to be at least twice the BLCK regardless of audio. Audio
driver has to probe using this hook and increase the clock even in
absence of any display.

v2: Use atomic refcount for get_power, put_power so that we can
    call each once(Abhay).
v3: Reset power well 2 to avoid any transaction on iDisp link
    during cdclk change(Abhay).
v4: Remove Power well 2 reset workaround(Ville).
v5: Remove unwanted Power well 2 register defined in v4(Abhay).
v6:
- Use a dedicated flag instead of state->modeset for min CDCLK changes
- Make get/put audio power domain symmetric
- Rebased on top of intel_wakeref tracking changes.

[jian-hong@endlessm.com: Rediff to keep i915_audio_component_get_power
 and i915_audio_component_put_power for Linux stable 5.1.x]
Cc: <stable@vger.kernel.org> # 5.1.x
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/20190320135439.12201-1-imre.deak@intel.com
---
 drivers/gpu/drm/i915/i915_drv.h      |  3 ++
 drivers/gpu/drm/i915/intel_audio.c   | 64 ++++++++++++++++++++++++++++++++++--
 drivers/gpu/drm/i915/intel_cdclk.c   | 30 ++++++-----------
 drivers/gpu/drm/i915/intel_display.c |  9 ++++-
 drivers/gpu/drm/i915/intel_drv.h     |  3 ++
 5 files changed, 85 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a67a63b5aa84..5c9bb1b2d1f3 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1622,6 +1622,8 @@ struct drm_i915_private {
 		struct intel_cdclk_state actual;
 		/* The current hardware cdclk state */
 		struct intel_cdclk_state hw;
+
+		int force_min_cdclk;
 	} cdclk;
 
 	/**
@@ -1741,6 +1743,7 @@ struct drm_i915_private {
 	 *
 	 */
 	struct mutex av_mutex;
+	int audio_power_refcount;
 
 	struct {
 		struct mutex mutex;
diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
index 5104c6bbd66f..5e044ca1e685 100644
--- a/drivers/gpu/drm/i915/intel_audio.c
+++ b/drivers/gpu/drm/i915/intel_audio.c
@@ -741,15 +741,73 @@ void intel_init_audio_hooks(struct drm_i915_private *dev_priv)
 	}
 }
 
+static void glk_force_audio_cdclk(struct drm_i915_private *dev_priv,
+				  bool enable)
+{
+	struct drm_modeset_acquire_ctx ctx;
+	struct drm_atomic_state *state;
+	int ret;
+
+	drm_modeset_acquire_init(&ctx, 0);
+	state = drm_atomic_state_alloc(&dev_priv->drm);
+	if (WARN_ON(!state))
+		return;
+
+	state->acquire_ctx = &ctx;
+
+retry:
+	to_intel_atomic_state(state)->cdclk.force_min_cdclk_changed = true;
+	to_intel_atomic_state(state)->cdclk.force_min_cdclk =
+		enable ? 2 * 96000 : 0;
+
+	/*
+	 * Protects dev_priv->cdclk.force_min_cdclk
+	 * Need to lock this here in case we have no active pipes
+	 * and thus wouldn't lock it during the commit otherwise.
+	 */
+	ret = drm_modeset_lock(&dev_priv->drm.mode_config.connection_mutex,
+			       &ctx);
+	if (!ret)
+		ret = drm_atomic_commit(state);
+
+	if (ret == -EDEADLK) {
+		drm_atomic_state_clear(state);
+		drm_modeset_backoff(&ctx);
+		goto retry;
+	}
+
+	WARN_ON(ret);
+
+	drm_atomic_state_put(state);
+
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
+}
+
 static void i915_audio_component_get_power(struct device *kdev)
 {
-	intel_display_power_get(kdev_to_i915(kdev), POWER_DOMAIN_AUDIO);
+	struct drm_i915_private *dev_priv = kdev_to_i915(kdev);
+
+	intel_display_power_get(dev_priv, POWER_DOMAIN_AUDIO);
+
+	/* Force CDCLK to 2*BCLK as long as we need audio to be powered. */
+	if (dev_priv->audio_power_refcount++ == 0)
+		if (IS_CANNONLAKE(dev_priv) || IS_GEMINILAKE(dev_priv))
+			glk_force_audio_cdclk(dev_priv, true);
 }
 
 static void i915_audio_component_put_power(struct device *kdev)
 {
-	intel_display_power_put_unchecked(kdev_to_i915(kdev),
-					  POWER_DOMAIN_AUDIO);
+	struct drm_i915_private *dev_priv = kdev_to_i915(kdev);
+	intel_wakeref_t cookie;
+
+	/* Stop forcing CDCLK to 2*BCLK if no need for audio to be powered. */
+	if (--dev_priv->audio_power_refcount == 0)
+		if (IS_CANNONLAKE(dev_priv) || IS_GEMINILAKE(dev_priv))
+			glk_force_audio_cdclk(dev_priv, false);
+
+	cookie = intel_display_power_get(dev_priv, POWER_DOMAIN_AUDIO);
+	intel_display_power_put(dev_priv, POWER_DOMAIN_AUDIO, cookie);
 }
 
 static void i915_audio_component_codec_wake_override(struct device *kdev,
diff --git a/drivers/gpu/drm/i915/intel_cdclk.c b/drivers/gpu/drm/i915/intel_cdclk.c
index 15ba950dee00..553f57ff60f4 100644
--- a/drivers/gpu/drm/i915/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/intel_cdclk.c
@@ -2187,19 +2187,8 @@ int intel_crtc_compute_min_cdclk(const struct intel_crtc_state *crtc_state)
 	/*
 	 * According to BSpec, "The CD clock frequency must be at least twice
 	 * the frequency of the Azalia BCLK." and BCLK is 96 MHz by default.
-	 *
-	 * FIXME: Check the actual, not default, BCLK being used.
-	 *
-	 * FIXME: This does not depend on ->has_audio because the higher CDCLK
-	 * is required for audio probe, also when there are no audio capable
-	 * displays connected at probe time. This leads to unnecessarily high
-	 * CDCLK when audio is not required.
-	 *
-	 * FIXME: This limit is only applied when there are displays connected
-	 * at probe time. If we probe without displays, we'll still end up using
-	 * the platform minimum CDCLK, failing audio probe.
 	 */
-	if (INTEL_GEN(dev_priv) >= 9)
+	if (crtc_state->has_audio && INTEL_GEN(dev_priv) >= 9)
 		min_cdclk = max(2 * 96000, min_cdclk);
 
 	/*
@@ -2239,7 +2228,7 @@ static int intel_compute_min_cdclk(struct drm_atomic_state *state)
 		intel_state->min_cdclk[i] = min_cdclk;
 	}
 
-	min_cdclk = 0;
+	min_cdclk = intel_state->cdclk.force_min_cdclk;
 	for_each_pipe(dev_priv, pipe)
 		min_cdclk = max(intel_state->min_cdclk[pipe], min_cdclk);
 
@@ -2300,7 +2289,8 @@ static int vlv_modeset_calc_cdclk(struct drm_atomic_state *state)
 		vlv_calc_voltage_level(dev_priv, cdclk);
 
 	if (!intel_state->active_crtcs) {
-		cdclk = vlv_calc_cdclk(dev_priv, 0);
+		cdclk = vlv_calc_cdclk(dev_priv,
+				       intel_state->cdclk.force_min_cdclk);
 
 		intel_state->cdclk.actual.cdclk = cdclk;
 		intel_state->cdclk.actual.voltage_level =
@@ -2333,7 +2323,7 @@ static int bdw_modeset_calc_cdclk(struct drm_atomic_state *state)
 		bdw_calc_voltage_level(cdclk);
 
 	if (!intel_state->active_crtcs) {
-		cdclk = bdw_calc_cdclk(0);
+		cdclk = bdw_calc_cdclk(intel_state->cdclk.force_min_cdclk);
 
 		intel_state->cdclk.actual.cdclk = cdclk;
 		intel_state->cdclk.actual.voltage_level =
@@ -2405,7 +2395,7 @@ static int skl_modeset_calc_cdclk(struct drm_atomic_state *state)
 		skl_calc_voltage_level(cdclk);
 
 	if (!intel_state->active_crtcs) {
-		cdclk = skl_calc_cdclk(0, vco);
+		cdclk = skl_calc_cdclk(intel_state->cdclk.force_min_cdclk, vco);
 
 		intel_state->cdclk.actual.vco = vco;
 		intel_state->cdclk.actual.cdclk = cdclk;
@@ -2444,10 +2434,10 @@ static int bxt_modeset_calc_cdclk(struct drm_atomic_state *state)
 
 	if (!intel_state->active_crtcs) {
 		if (IS_GEMINILAKE(dev_priv)) {
-			cdclk = glk_calc_cdclk(0);
+			cdclk = glk_calc_cdclk(intel_state->cdclk.force_min_cdclk);
 			vco = glk_de_pll_vco(dev_priv, cdclk);
 		} else {
-			cdclk = bxt_calc_cdclk(0);
+			cdclk = bxt_calc_cdclk(intel_state->cdclk.force_min_cdclk);
 			vco = bxt_de_pll_vco(dev_priv, cdclk);
 		}
 
@@ -2483,7 +2473,7 @@ static int cnl_modeset_calc_cdclk(struct drm_atomic_state *state)
 		    cnl_compute_min_voltage_level(intel_state));
 
 	if (!intel_state->active_crtcs) {
-		cdclk = cnl_calc_cdclk(0);
+		cdclk = cnl_calc_cdclk(intel_state->cdclk.force_min_cdclk);
 		vco = cnl_cdclk_pll_vco(dev_priv, cdclk);
 
 		intel_state->cdclk.actual.vco = vco;
@@ -2519,7 +2509,7 @@ static int icl_modeset_calc_cdclk(struct drm_atomic_state *state)
 		    cnl_compute_min_voltage_level(intel_state));
 
 	if (!intel_state->active_crtcs) {
-		cdclk = icl_calc_cdclk(0, ref);
+		cdclk = icl_calc_cdclk(intel_state->cdclk.force_min_cdclk, ref);
 		vco = icl_calc_cdclk_pll_vco(dev_priv, cdclk);
 
 		intel_state->cdclk.actual.vco = vco;
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 421aac80a838..ebbac873b8f4 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12769,6 +12769,11 @@ static int intel_modeset_checks(struct drm_atomic_state *state)
 		return -EINVAL;
 	}
 
+	/* keep the current setting */
+	if (!intel_state->cdclk.force_min_cdclk_changed)
+		intel_state->cdclk.force_min_cdclk =
+			dev_priv->cdclk.force_min_cdclk;
+
 	intel_state->modeset = true;
 	intel_state->active_crtcs = dev_priv->active_crtcs;
 	intel_state->cdclk.logical = dev_priv->cdclk.logical;
@@ -12864,7 +12869,7 @@ static int intel_atomic_check(struct drm_device *dev,
 	struct drm_crtc *crtc;
 	struct drm_crtc_state *old_crtc_state, *crtc_state;
 	int ret, i;
-	bool any_ms = false;
+	bool any_ms = intel_state->cdclk.force_min_cdclk_changed;
 
 	/* Catch I915_MODE_FLAG_INHERITED */
 	for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state,
@@ -13456,6 +13461,8 @@ static int intel_atomic_commit(struct drm_device *dev,
 		dev_priv->active_crtcs = intel_state->active_crtcs;
 		dev_priv->cdclk.logical = intel_state->cdclk.logical;
 		dev_priv->cdclk.actual = intel_state->cdclk.actual;
+		dev_priv->cdclk.force_min_cdclk =
+			intel_state->cdclk.force_min_cdclk;
 	}
 
 	drm_atomic_state_get(state);
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index d5660ac1b0d6..539caca05da4 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -480,6 +480,9 @@ struct intel_atomic_state {
 		 * state only when all crtc's are DPMS off.
 		 */
 		struct intel_cdclk_state actual;
+
+		int force_min_cdclk;
+		bool force_min_cdclk_changed;
 	} cdclk;
 
 	bool dpll_set, modeset;
-- 
2.11.0

Re: [PATCH 5.1 stable] drm/i915: Force 2*96 MHz cdclk on glk/cnl when audio power is enabled

[Daniel Drake]

On Mon, Jun 3, 2019 at 4:27 PM Jian-Hong Pan <jian-hong@endlessm.com> wrote:
>  static void i915_audio_component_get_power(struct device *kdev)
>  {
> -       intel_display_power_get(kdev_to_i915(kdev), POWER_DOMAIN_AUDIO);
> +       struct drm_i915_private *dev_priv = kdev_to_i915(kdev);
> +
> +       intel_display_power_get(dev_priv, POWER_DOMAIN_AUDIO);
> +
> +       /* Force CDCLK to 2*BCLK as long as we need audio to be powered. */
> +       if (dev_priv->audio_power_refcount++ == 0)
> +               if (IS_CANNONLAKE(dev_priv) || IS_GEMINILAKE(dev_priv))
> +                       glk_force_audio_cdclk(dev_priv, true);
>  }
>
>  static void i915_audio_component_put_power(struct device *kdev)
>  {
> -       intel_display_power_put_unchecked(kdev_to_i915(kdev),
> -                                         POWER_DOMAIN_AUDIO);
> +       struct drm_i915_private *dev_priv = kdev_to_i915(kdev);
> +       intel_wakeref_t cookie;
> +
> +       /* Stop forcing CDCLK to 2*BCLK if no need for audio to be powered. */
> +       if (--dev_priv->audio_power_refcount == 0)
> +               if (IS_CANNONLAKE(dev_priv) || IS_GEMINILAKE(dev_priv))
> +                       glk_force_audio_cdclk(dev_priv, false);
> +
> +       cookie = intel_display_power_get(dev_priv, POWER_DOMAIN_AUDIO);
> +       intel_display_power_put(dev_priv, POWER_DOMAIN_AUDIO, cookie);
>  }

The code above is the rediffed part of the patch. I think the last 2
lines here are not quite right.

Here, get means "increment reference count" and put means "decrease
reference count".

Before your patch, i915_audio_component_get_power() does
intel_display_power_get(), and i915_audio_component_put_power() does
intel_display_power_put_unchecked(). You can see the symmetry.

After your patch, i915_audio_component_get_power() does
intel_display_power_get() as before (good), but
i915_audio_component_put_power() does a 2nd get and then a single put.
So the reference count is now unbalanced.

I think the last 2 lines of this function should just be left the same
as they were before:
       intel_display_power_put_unchecked(kdev_to_i915(kdev),
                                         POWER_DOMAIN_AUDIO);

Daniel

Re: [PATCH 5.1 stable] drm/i915: Force 2*96 MHz cdclk on glk/cnl when audio power is enabled

[Jian-Hong Pan]

Daniel Drake <drake@endlessm.com> 於 2019年6月3日 週一 下午4:47寫道：
>
> On Mon, Jun 3, 2019 at 4:27 PM Jian-Hong Pan <jian-hong@endlessm.com> wrote:
> >  static void i915_audio_component_get_power(struct device *kdev)
> >  {
> > -       intel_display_power_get(kdev_to_i915(kdev), POWER_DOMAIN_AUDIO);
> > +       struct drm_i915_private *dev_priv = kdev_to_i915(kdev);
> > +
> > +       intel_display_power_get(dev_priv, POWER_DOMAIN_AUDIO);
> > +
> > +       /* Force CDCLK to 2*BCLK as long as we need audio to be powered. */
> > +       if (dev_priv->audio_power_refcount++ == 0)
> > +               if (IS_CANNONLAKE(dev_priv) || IS_GEMINILAKE(dev_priv))
> > +                       glk_force_audio_cdclk(dev_priv, true);
> >  }
> >
> >  static void i915_audio_component_put_power(struct device *kdev)
> >  {
> > -       intel_display_power_put_unchecked(kdev_to_i915(kdev),
> > -                                         POWER_DOMAIN_AUDIO);
> > +       struct drm_i915_private *dev_priv = kdev_to_i915(kdev);
> > +       intel_wakeref_t cookie;
> > +
> > +       /* Stop forcing CDCLK to 2*BCLK if no need for audio to be powered. */
> > +       if (--dev_priv->audio_power_refcount == 0)
> > +               if (IS_CANNONLAKE(dev_priv) || IS_GEMINILAKE(dev_priv))
> > +                       glk_force_audio_cdclk(dev_priv, false);
> > +
> > +       cookie = intel_display_power_get(dev_priv, POWER_DOMAIN_AUDIO);
> > +       intel_display_power_put(dev_priv, POWER_DOMAIN_AUDIO, cookie);
> >  }
>
> The code above is the rediffed part of the patch. I think the last 2
> lines here are not quite right.
>
> Here, get means "increment reference count" and put means "decrease
> reference count".
>
> Before your patch, i915_audio_component_get_power() does
> intel_display_power_get(), and i915_audio_component_put_power() does
> intel_display_power_put_unchecked(). You can see the symmetry.
>
> After your patch, i915_audio_component_get_power() does
> intel_display_power_get() as before (good), but
> i915_audio_component_put_power() does a 2nd get and then a single put.
> So the reference count is now unbalanced.
>
> I think the last 2 lines of this function should just be left the same
> as they were before:
>        intel_display_power_put_unchecked(kdev_to_i915(kdev),
>                                          POWER_DOMAIN_AUDIO);

Hi Daniel,

Thanks for your reviewing.
I'm going to prepare new Rediff.

Jian-Hong Pan