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Commit fbf6d879 authored by Maarten Lankhorst's avatar Maarten Lankhorst
Browse files

drm/i915: Add locking to pll updates, v3. 



With async modesets this is no longer protected with connection_mutex,
so ensure that each pll has its own lock. The pll configuration state
is still protected; it's only the pll updates that need locking against
concurrency.

Changes since v1:
- Rebased.
- Fix locking to protect all accesses. (Durgadoss)
Changes since v2:
- Make the dpll_lock global to protect concurrent updates to the
  same register, for example DPLL_CTRL1 on skl. (Ander)

Signed-off-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/56F29F50.1090708@linux.intel.com


Reviewed-by: default avatarAnder Conselvan de Oliveira <conselvan2@gmail.com>
parent 55c561a7

drivers/gpu/drm/i915/i915_drv.h

+7 −0
Original line number Diff line number Diff line
@@ -1837,6 +1837,13 @@ struct drm_i915_private { 
	struct intel_shared_dpll shared_dplls[I915_NUM_PLLS];

	const struct intel_dpll_mgr *dpll_mgr;



	/*

	 * dpll_lock serializes intel_{prepare,enable,disable}_shared_dpll.

	 * Must be global rather than per dpll, because on some platforms

	 * plls share registers.

	 */

	struct mutex dpll_lock;



	unsigned int active_crtcs;

	unsigned int min_pixclk[I915_MAX_PIPES];

drivers/gpu/drm/i915/intel_dpll_mgr.c

+19 −6
Original line number Diff line number Diff line
@@ -89,14 +89,16 @@ void intel_prepare_shared_dpll(struct intel_crtc *crtc) 
	if (WARN_ON(pll == NULL))

		return;



	mutex_lock(&dev_priv->dpll_lock);

	WARN_ON(!pll->config.crtc_mask);

	if (pll->active_mask == 0) {

	if (!pll->active_mask) {

		DRM_DEBUG_DRIVER("setting up %s\n", pll->name);

		WARN_ON(pll->on);

		assert_shared_dpll_disabled(dev_priv, pll);



		pll->funcs.mode_set(dev_priv, pll);

	}

	mutex_unlock(&dev_priv->dpll_lock);

}



/**
@@ -113,14 +115,17 @@ void intel_enable_shared_dpll(struct intel_crtc *crtc) 
	struct drm_i915_private *dev_priv = dev->dev_private;

	struct intel_shared_dpll *pll = crtc->config->shared_dpll;

	unsigned crtc_mask = 1 << drm_crtc_index(&crtc->base);

	unsigned old_mask = pll->active_mask;

	unsigned old_mask;



	if (WARN_ON(pll == NULL))

		return;



	mutex_lock(&dev_priv->dpll_lock);

	old_mask = pll->active_mask;



	if (WARN_ON(!(pll->config.crtc_mask & crtc_mask)) ||

	    WARN_ON(pll->active_mask & crtc_mask))

		return;

		goto out;



	pll->active_mask |= crtc_mask;
@@ -131,13 +136,16 @@ void intel_enable_shared_dpll(struct intel_crtc *crtc) 
	if (old_mask) {

		WARN_ON(!pll->on);

		assert_shared_dpll_enabled(dev_priv, pll);

		return;

		goto out;

	}

	WARN_ON(pll->on);



	DRM_DEBUG_KMS("enabling %s\n", pll->name);

	pll->funcs.enable(dev_priv, pll);

	pll->on = true;



out:

	mutex_unlock(&dev_priv->dpll_lock);

}



void intel_disable_shared_dpll(struct intel_crtc *crtc)
@@ -154,8 +162,9 @@ void intel_disable_shared_dpll(struct intel_crtc *crtc) 
	if (pll == NULL)

		return;



	mutex_lock(&dev_priv->dpll_lock);

	if (WARN_ON(!(pll->active_mask & crtc_mask)))

		return;

		goto out;



	DRM_DEBUG_KMS("disable %s (active %x, on? %d) for crtc %d\n",

		      pll->name, pll->active_mask, pll->on,
@@ -166,11 +175,14 @@ void intel_disable_shared_dpll(struct intel_crtc *crtc) 


	pll->active_mask &= ~crtc_mask;

	if (pll->active_mask)

		return;

		goto out;



	DRM_DEBUG_KMS("disabling %s\n", pll->name);

	pll->funcs.disable(dev_priv, pll);

	pll->on = false;



out:

	mutex_unlock(&dev_priv->dpll_lock);

}



static struct intel_shared_dpll *
@@ -1750,6 +1762,7 @@ void intel_shared_dpll_init(struct drm_device *dev) 


	dev_priv->dpll_mgr = dpll_mgr;

	dev_priv->num_shared_dpll = i;

	mutex_init(&dev_priv->dpll_lock);



	BUG_ON(dev_priv->num_shared_dpll > I915_NUM_PLLS);