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/*

 * Copyright © 2014 Intel Corporation

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice (including the next

 * paragraph) shall be included in all copies or substantial portions of the

 * Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

 * DEALINGS IN THE SOFTWARE.

 *

 * Authors:

 *	Daniel Vetter 

 */

/**

 * DOC: frontbuffer tracking

 *

 * Many features require us to track changes to the currently active

 * frontbuffer, especially rendering targeted at the frontbuffer.

 *

 * To be able to do so GEM tracks frontbuffers using a bitmask for all possible

 * frontbuffer slots through i915_gem_track_fb(). The function in this file are

 * then called when the contents of the frontbuffer are invalidated, when

 * frontbuffer rendering has stopped again to flush out all the changes and when

 * the frontbuffer is exchanged with a flip. Subsystems interested in

 * frontbuffer changes (e.g. PSR, FBC, DRRS) should directly put their callbacks

 * into the relevant places and filter for the frontbuffer slots that they are

 * interested int.

 *

 * On a high level there are two types of powersaving features. The first one

 * work like a special cache (FBC and PSR) and are interested when they should

 * stop caching and when to restart caching. This is done by placing callbacks

 * into the invalidate and the flush functions: At invalidate the caching must

 * be stopped and at flush time it can be restarted. And maybe they need to know

 * when the frontbuffer changes (e.g. when the hw doesn't initiate an invalidate

 * and flush on its own) which can be achieved with placing callbacks into the

 * flip functions.

 *

 * The other type of display power saving feature only cares about busyness

 * (e.g. DRRS). In that case all three (invalidate, flush and flip) indicate

 * busyness. There is no direct way to detect idleness. Instead an idle timer

 * work delayed work should be started from the flush and flip functions and

 * cancelled as soon as busyness is detected.

 *

 * Note that there's also an older frontbuffer activity tracking scheme which

 * just tracks general activity. This is done by the various mark_busy and

 * mark_idle functions. For display power management features using these

 * functions is deprecated and should be avoided.

 */

#include 

#include "intel_drv.h"

#include "i915_drv.h"

static void intel_increase_pllclock(struct drm_device *dev,

				    enum pipe pipe)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	int dpll_reg = DPLL(pipe);

	int dpll;

	if (!HAS_GMCH_DISPLAY(dev))

		return;

	if (!dev_priv->lvds_downclock_avail)

		return;

	dpll = I915_READ(dpll_reg);

	if (!HAS_PIPE_CXSR(dev) && (dpll & DISPLAY_RATE_SELECT_FPA1)) {

		DRM_DEBUG_DRIVER("upclocking LVDS\n");

		assert_panel_unlocked(dev_priv, pipe);

		dpll &= ~DISPLAY_RATE_SELECT_FPA1;

		I915_WRITE(dpll_reg, dpll);

		intel_wait_for_vblank(dev, pipe);

		dpll = I915_READ(dpll_reg);

		if (dpll & DISPLAY_RATE_SELECT_FPA1)

			DRM_DEBUG_DRIVER("failed to upclock LVDS!\n");

	}

}

/**

 * intel_mark_fb_busy - mark given planes as busy

 * @dev: DRM device

 * @frontbuffer_bits: bits for the affected planes

 * @ring: optional ring for asynchronous commands

 *

 * This function gets called every time the screen contents change. It can be

 * used to keep e.g. the update rate at the nominal refresh rate with DRRS.

 */

static void intel_mark_fb_busy(struct drm_device *dev,

			       unsigned frontbuffer_bits,

			       struct intel_engine_cs *ring)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	enum pipe pipe;

	if (!i915.powersave)

		return;

	for_each_pipe(dev_priv, pipe) {

		if (!(frontbuffer_bits & INTEL_FRONTBUFFER_ALL_MASK(pipe)))

			continue;

		intel_increase_pllclock(dev, pipe);

		if (ring && intel_fbc_enabled(dev))

			ring->fbc_dirty = true;

	}

}

/**

 * intel_fb_obj_invalidate - invalidate frontbuffer object

 * @obj: GEM object to invalidate

 * @ring: set for asynchronous rendering

 *

 * This function gets called every time rendering on the given object starts and

 * frontbuffer caching (fbc, low refresh rate for DRRS, panel self refresh) must

 * be invalidated. If @ring is non-NULL any subsequent invalidation will be delayed

 * until the rendering completes or a flip on this frontbuffer plane is

 * scheduled.

 */

void intel_fb_obj_invalidate(struct drm_i915_gem_object *obj,

			     struct intel_engine_cs *ring)

{

	struct drm_device *dev = obj->base.dev;

	struct drm_i915_private *dev_priv = dev->dev_private;

	WARN_ON(!mutex_is_locked(&dev->struct_mutex));

	if (!obj->frontbuffer_bits)

		return;

	if (ring) {

		mutex_lock(&dev_priv->fb_tracking.lock);

		dev_priv->fb_tracking.busy_bits

			|= obj->frontbuffer_bits;

		dev_priv->fb_tracking.flip_bits

			&= ~obj->frontbuffer_bits;

		mutex_unlock(&dev_priv->fb_tracking.lock);

	}

	intel_mark_fb_busy(dev, obj->frontbuffer_bits, ring);

	intel_psr_invalidate(dev, obj->frontbuffer_bits);

}

/**

 * intel_frontbuffer_flush - flush frontbuffer

 * @dev: DRM device

 * @frontbuffer_bits: frontbuffer plane tracking bits

 *

 * This function gets called every time rendering on the given planes has

 * completed and frontbuffer caching can be started again. Flushes will get

 * delayed if they're blocked by some outstanding asynchronous rendering.

 *

 * Can be called without any locks held.

 */

void intel_frontbuffer_flush(struct drm_device *dev,

			     unsigned frontbuffer_bits)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	/* Delay flushing when rings are still busy.*/

	mutex_lock(&dev_priv->fb_tracking.lock);

	frontbuffer_bits &= ~dev_priv->fb_tracking.busy_bits;

	mutex_unlock(&dev_priv->fb_tracking.lock);

	intel_mark_fb_busy(dev, frontbuffer_bits, NULL);

	intel_psr_flush(dev, frontbuffer_bits);

	/*

	 * FIXME: Unconditional fbc flushing here is a rather gross hack and

	 * needs to be reworked into a proper frontbuffer tracking scheme like

	 * psr employs.

	 */

	if (dev_priv->fbc.need_sw_cache_clean) {

		dev_priv->fbc.need_sw_cache_clean = false;

		bdw_fbc_sw_flush(dev, FBC_REND_CACHE_CLEAN);

	}

}

/**

 * intel_fb_obj_flush - flush frontbuffer object

 * @obj: GEM object to flush

 * @retire: set when retiring asynchronous rendering

 *

 * This function gets called every time rendering on the given object has

 * completed and frontbuffer caching can be started again. If @retire is true

 * then any delayed flushes will be unblocked.

 */

void intel_fb_obj_flush(struct drm_i915_gem_object *obj,

			bool retire)

{

	struct drm_device *dev = obj->base.dev;

	struct drm_i915_private *dev_priv = dev->dev_private;

	unsigned frontbuffer_bits;

	WARN_ON(!mutex_is_locked(&dev->struct_mutex));

	if (!obj->frontbuffer_bits)

		return;

	frontbuffer_bits = obj->frontbuffer_bits;

	if (retire) {

		mutex_lock(&dev_priv->fb_tracking.lock);

		/* Filter out new bits since rendering started. */

		frontbuffer_bits &= dev_priv->fb_tracking.busy_bits;

		dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;

		mutex_unlock(&dev_priv->fb_tracking.lock);

	}

	intel_frontbuffer_flush(dev, frontbuffer_bits);

}

/**

 * intel_frontbuffer_flip_prepare - prepare asynchronous frontbuffer flip

 * @dev: DRM device

 * @frontbuffer_bits: frontbuffer plane tracking bits

 *

 * This function gets called after scheduling a flip on @obj. The actual

 * frontbuffer flushing will be delayed until completion is signalled with

 * intel_frontbuffer_flip_complete. If an invalidate happens in between this

 * flush will be cancelled.

 *

 * Can be called without any locks held.

 */

void intel_frontbuffer_flip_prepare(struct drm_device *dev,

				    unsigned frontbuffer_bits)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	mutex_lock(&dev_priv->fb_tracking.lock);

	dev_priv->fb_tracking.flip_bits |= frontbuffer_bits;

	/* Remove stale busy bits due to the old buffer. */

	dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;

	mutex_unlock(&dev_priv->fb_tracking.lock);

}

/**

 * intel_frontbuffer_flip_complete - complete asynchronous frontbuffer flip

 * @dev: DRM device

 * @frontbuffer_bits: frontbuffer plane tracking bits

 *

 * This function gets called after the flip has been latched and will complete

 * on the next vblank. It will execute the flush if it hasn't been cancelled yet.

 *

 * Can be called without any locks held.

 */

void intel_frontbuffer_flip_complete(struct drm_device *dev,

				     unsigned frontbuffer_bits)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	mutex_lock(&dev_priv->fb_tracking.lock);

	/* Mask any cancelled flips. */

	frontbuffer_bits &= dev_priv->fb_tracking.flip_bits;

	dev_priv->fb_tracking.flip_bits &= ~frontbuffer_bits;

	mutex_unlock(&dev_priv->fb_tracking.lock);

	intel_frontbuffer_flush(dev, frontbuffer_bits);

}