drivers/gpu/drm/i915/intel_frontbuffer.c

   1 /*
   2  * Copyright © 2014 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *      Daniel Vetter <daniel.vetter@ffwll.ch>
  25  */
  26
  27 /**
  28  * DOC: frontbuffer tracking
  29  *
  30  * Many features require us to track changes to the currently active
  31  * frontbuffer, especially rendering targeted at the frontbuffer.
  32  *
  33  * To be able to do so GEM tracks frontbuffers using a bitmask for all possible
  34  * frontbuffer slots through i915_gem_track_fb(). The function in this file are
  35  * then called when the contents of the frontbuffer are invalidated, when
  36  * frontbuffer rendering has stopped again to flush out all the changes and when
  37  * the frontbuffer is exchanged with a flip. Subsystems interested in
  38  * frontbuffer changes (e.g. PSR, FBC, DRRS) should directly put their callbacks
  39  * into the relevant places and filter for the frontbuffer slots that they are
  40  * interested int.
  41  *
  42  * On a high level there are two types of powersaving features. The first one
  43  * work like a special cache (FBC and PSR) and are interested when they should
  44  * stop caching and when to restart caching. This is done by placing callbacks
  45  * into the invalidate and the flush functions: At invalidate the caching must
  46  * be stopped and at flush time it can be restarted. And maybe they need to know
  47  * when the frontbuffer changes (e.g. when the hw doesn't initiate an invalidate
  48  * and flush on its own) which can be achieved with placing callbacks into the
  49  * flip functions.
  50  *
  51  * The other type of display power saving feature only cares about busyness
  52  * (e.g. DRRS). In that case all three (invalidate, flush and flip) indicate
  53  * busyness. There is no direct way to detect idleness. Instead an idle timer
  54  * work delayed work should be started from the flush and flip functions and
  55  * cancelled as soon as busyness is detected.
  56  *
  57  * Note that there's also an older frontbuffer activity tracking scheme which
  58  * just tracks general activity. This is done by the various mark_busy and
  59  * mark_idle functions. For display power management features using these
  60  * functions is deprecated and should be avoided.
  61  */
  62
  63 #include <drm/drmP.h>
  64
  65 #include "intel_drv.h"
  66 #include "i915_drv.h"
  67
  68 /**
  69  * intel_fb_obj_invalidate - invalidate frontbuffer object
  70  * @obj: GEM object to invalidate
  71  * @origin: which operation caused the invalidation
  72  *
  73  * This function gets called every time rendering on the given object starts and
  74  * frontbuffer caching (fbc, low refresh rate for DRRS, panel self refresh) must
  75  * be invalidated. For ORIGIN_CS any subsequent invalidation will be delayed
  76  * until the rendering completes or a flip on this frontbuffer plane is
  77  * scheduled.
  78  */
  79 void intel_fb_obj_invalidate(struct drm_i915_gem_object *obj,
  80                              enum fb_op_origin origin)
  81 {
  82         struct drm_device *dev = obj->base.dev;
  83         struct drm_i915_private *dev_priv = to_i915(dev);
  84
  85         WARN_ON(!mutex_is_locked(&dev->struct_mutex));
  86
  87         if (!obj->frontbuffer_bits)
  88                 return;
  89
  90         if (origin == ORIGIN_CS) {
  91                 mutex_lock(&dev_priv->fb_tracking.lock);
  92                 dev_priv->fb_tracking.busy_bits
  93                         |= obj->frontbuffer_bits;
  94                 dev_priv->fb_tracking.flip_bits
  95                         &= ~obj->frontbuffer_bits;
  96                 mutex_unlock(&dev_priv->fb_tracking.lock);
  97         }
  98
  99         intel_psr_invalidate(dev, obj->frontbuffer_bits);
 100         intel_edp_drrs_invalidate(dev, obj->frontbuffer_bits);
 101         intel_fbc_invalidate(dev_priv, obj->frontbuffer_bits, origin);
 102 }
 103
 104 /**
 105  * intel_frontbuffer_flush - flush frontbuffer
 106  * @dev: DRM device
 107  * @frontbuffer_bits: frontbuffer plane tracking bits
 108  * @origin: which operation caused the flush
 109  *
 110  * This function gets called every time rendering on the given planes has
 111  * completed and frontbuffer caching can be started again. Flushes will get
 112  * delayed if they're blocked by some outstanding asynchronous rendering.
 113  *
 114  * Can be called without any locks held.
 115  */
 116 static void intel_frontbuffer_flush(struct drm_device *dev,
 117                                     unsigned frontbuffer_bits,
 118                                     enum fb_op_origin origin)
 119 {
 120         struct drm_i915_private *dev_priv = to_i915(dev);
 121
 122         /* Delay flushing when rings are still busy.*/
 123         mutex_lock(&dev_priv->fb_tracking.lock);
 124         frontbuffer_bits &= ~dev_priv->fb_tracking.busy_bits;
 125         mutex_unlock(&dev_priv->fb_tracking.lock);
 126
 127         if (!frontbuffer_bits)
 128                 return;
 129
 130         intel_edp_drrs_flush(dev, frontbuffer_bits);
 131         intel_psr_flush(dev, frontbuffer_bits, origin);
 132         intel_fbc_flush(dev_priv, frontbuffer_bits, origin);
 133 }
 134
 135 /**
 136  * intel_fb_obj_flush - flush frontbuffer object
 137  * @obj: GEM object to flush
 138  * @retire: set when retiring asynchronous rendering
 139  * @origin: which operation caused the flush
 140  *
 141  * This function gets called every time rendering on the given object has
 142  * completed and frontbuffer caching can be started again. If @retire is true
 143  * then any delayed flushes will be unblocked.
 144  */
 145 void intel_fb_obj_flush(struct drm_i915_gem_object *obj,
 146                         bool retire, enum fb_op_origin origin)
 147 {
 148         struct drm_device *dev = obj->base.dev;
 149         struct drm_i915_private *dev_priv = to_i915(dev);
 150         unsigned frontbuffer_bits;
 151
 152         WARN_ON(!mutex_is_locked(&dev->struct_mutex));
 153
 154         if (!obj->frontbuffer_bits)
 155                 return;
 156
 157         frontbuffer_bits = obj->frontbuffer_bits;
 158
 159         if (retire) {
 160                 mutex_lock(&dev_priv->fb_tracking.lock);
 161                 /* Filter out new bits since rendering started. */
 162                 frontbuffer_bits &= dev_priv->fb_tracking.busy_bits;
 163
 164                 dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
 165                 mutex_unlock(&dev_priv->fb_tracking.lock);
 166         }
 167
 168         intel_frontbuffer_flush(dev, frontbuffer_bits, origin);
 169 }
 170
 171 /**
 172  * intel_frontbuffer_flip_prepare - prepare asynchronous frontbuffer flip
 173  * @dev: DRM device
 174  * @frontbuffer_bits: frontbuffer plane tracking bits
 175  *
 176  * This function gets called after scheduling a flip on @obj. The actual
 177  * frontbuffer flushing will be delayed until completion is signalled with
 178  * intel_frontbuffer_flip_complete. If an invalidate happens in between this
 179  * flush will be cancelled.
 180  *
 181  * Can be called without any locks held.
 182  */
 183 void intel_frontbuffer_flip_prepare(struct drm_device *dev,
 184                                     unsigned frontbuffer_bits)
 185 {
 186         struct drm_i915_private *dev_priv = to_i915(dev);
 187
 188         mutex_lock(&dev_priv->fb_tracking.lock);
 189         dev_priv->fb_tracking.flip_bits |= frontbuffer_bits;
 190         /* Remove stale busy bits due to the old buffer. */
 191         dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
 192         mutex_unlock(&dev_priv->fb_tracking.lock);
 193
 194         intel_psr_single_frame_update(dev, frontbuffer_bits);
 195 }
 196
 197 /**
 198  * intel_frontbuffer_flip_complete - complete asynchronous frontbuffer flip
 199  * @dev: DRM device
 200  * @frontbuffer_bits: frontbuffer plane tracking bits
 201  *
 202  * This function gets called after the flip has been latched and will complete
 203  * on the next vblank. It will execute the flush if it hasn't been cancelled yet.
 204  *
 205  * Can be called without any locks held.
 206  */
 207 void intel_frontbuffer_flip_complete(struct drm_device *dev,
 208                                      unsigned frontbuffer_bits)
 209 {
 210         struct drm_i915_private *dev_priv = to_i915(dev);
 211
 212         mutex_lock(&dev_priv->fb_tracking.lock);
 213         /* Mask any cancelled flips. */
 214         frontbuffer_bits &= dev_priv->fb_tracking.flip_bits;
 215         dev_priv->fb_tracking.flip_bits &= ~frontbuffer_bits;
 216         mutex_unlock(&dev_priv->fb_tracking.lock);
 217
 218         intel_frontbuffer_flush(dev, frontbuffer_bits, ORIGIN_FLIP);
 219 }
 220
 221 /**
 222  * intel_frontbuffer_flip - synchronous frontbuffer flip
 223  * @dev: DRM device
 224  * @frontbuffer_bits: frontbuffer plane tracking bits
 225  *
 226  * This function gets called after scheduling a flip on @obj. This is for
 227  * synchronous plane updates which will happen on the next vblank and which will
 228  * not get delayed by pending gpu rendering.
 229  *
 230  * Can be called without any locks held.
 231  */
 232 void intel_frontbuffer_flip(struct drm_device *dev,
 233                             unsigned frontbuffer_bits)
 234 {
 235         struct drm_i915_private *dev_priv = to_i915(dev);
 236
 237         mutex_lock(&dev_priv->fb_tracking.lock);
 238         /* Remove stale busy bits due to the old buffer. */
 239         dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
 240         mutex_unlock(&dev_priv->fb_tracking.lock);
 241
 242         intel_frontbuffer_flush(dev, frontbuffer_bits, ORIGIN_FLIP);
 243 }