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 static void intel_increase_pllclock(struct drm_device *dev,
  69                                     enum pipe pipe)
  70 {
  71         struct drm_i915_private *dev_priv = dev->dev_private;
  72         int dpll_reg = DPLL(pipe);
  73         int dpll;
  74
  75         if (!HAS_GMCH_DISPLAY(dev))
  76                 return;
  77
  78         if (!dev_priv->lvds_downclock_avail)
  79                 return;
  80
  81         dpll = I915_READ(dpll_reg);
  82         if (!HAS_PIPE_CXSR(dev) && (dpll & DISPLAY_RATE_SELECT_FPA1)) {
  83                 DRM_DEBUG_DRIVER("upclocking LVDS\n");
  84
  85                 assert_panel_unlocked(dev_priv, pipe);
  86
  87                 dpll &= ~DISPLAY_RATE_SELECT_FPA1;
  88                 I915_WRITE(dpll_reg, dpll);
  89                 intel_wait_for_vblank(dev, pipe);
  90
  91                 dpll = I915_READ(dpll_reg);
  92                 if (dpll & DISPLAY_RATE_SELECT_FPA1)
  93                         DRM_DEBUG_DRIVER("failed to upclock LVDS!\n");
  94         }
  95 }
  96
  97 /**
  98  * intel_mark_fb_busy - mark given planes as busy
  99  * @dev: DRM device
 100  * @frontbuffer_bits: bits for the affected planes
 101  * @ring: optional ring for asynchronous commands
 102  *
 103  * This function gets called every time the screen contents change. It can be
 104  * used to keep e.g. the update rate at the nominal refresh rate with DRRS.
 105  */
 106 static void intel_mark_fb_busy(struct drm_device *dev,
 107                                unsigned frontbuffer_bits,
 108                                struct intel_engine_cs *ring)
 109 {
 110         struct drm_i915_private *dev_priv = dev->dev_private;
 111         enum pipe pipe;
 112
 113         for_each_pipe(dev_priv, pipe) {
 114                 if (!(frontbuffer_bits & INTEL_FRONTBUFFER_ALL_MASK(pipe)))
 115                         continue;
 116
 117                 intel_increase_pllclock(dev, pipe);
 118         }
 119 }
 120
 121 /**
 122  * intel_fb_obj_invalidate - invalidate frontbuffer object
 123  * @obj: GEM object to invalidate
 124  * @ring: set for asynchronous rendering
 125  * @origin: which operation caused the invalidation
 126  *
 127  * This function gets called every time rendering on the given object starts and
 128  * frontbuffer caching (fbc, low refresh rate for DRRS, panel self refresh) must
 129  * be invalidated. If @ring is non-NULL any subsequent invalidation will be delayed
 130  * until the rendering completes or a flip on this frontbuffer plane is
 131  * scheduled.
 132  */
 133 void intel_fb_obj_invalidate(struct drm_i915_gem_object *obj,
 134                              struct intel_engine_cs *ring,
 135                              enum fb_op_origin origin)
 136 {
 137         struct drm_device *dev = obj->base.dev;
 138         struct drm_i915_private *dev_priv = dev->dev_private;
 139
 140         WARN_ON(!mutex_is_locked(&dev->struct_mutex));
 141
 142         if (!obj->frontbuffer_bits)
 143                 return;
 144
 145         if (ring) {
 146                 mutex_lock(&dev_priv->fb_tracking.lock);
 147                 dev_priv->fb_tracking.busy_bits
 148                         |= obj->frontbuffer_bits;
 149                 dev_priv->fb_tracking.flip_bits
 150                         &= ~obj->frontbuffer_bits;
 151                 mutex_unlock(&dev_priv->fb_tracking.lock);
 152         }
 153
 154         intel_mark_fb_busy(dev, obj->frontbuffer_bits, ring);
 155
 156         intel_psr_invalidate(dev, obj->frontbuffer_bits);
 157         intel_edp_drrs_invalidate(dev, obj->frontbuffer_bits);
 158         intel_fbc_invalidate(dev_priv, obj->frontbuffer_bits, origin);
 159 }
 160
 161 /**
 162  * intel_frontbuffer_flush - flush frontbuffer
 163  * @dev: DRM device
 164  * @frontbuffer_bits: frontbuffer plane tracking bits
 165  *
 166  * This function gets called every time rendering on the given planes has
 167  * completed and frontbuffer caching can be started again. Flushes will get
 168  * delayed if they're blocked by some outstanding asynchronous rendering.
 169  *
 170  * Can be called without any locks held.
 171  */
 172 void intel_frontbuffer_flush(struct drm_device *dev,
 173                              unsigned frontbuffer_bits)
 174 {
 175         struct drm_i915_private *dev_priv = dev->dev_private;
 176
 177         /* Delay flushing when rings are still busy.*/
 178         mutex_lock(&dev_priv->fb_tracking.lock);
 179         frontbuffer_bits &= ~dev_priv->fb_tracking.busy_bits;
 180         mutex_unlock(&dev_priv->fb_tracking.lock);
 181
 182         intel_mark_fb_busy(dev, frontbuffer_bits, NULL);
 183
 184         intel_edp_drrs_flush(dev, frontbuffer_bits);
 185         intel_psr_flush(dev, frontbuffer_bits);
 186         intel_fbc_flush(dev_priv, frontbuffer_bits);
 187 }
 188
 189 /**
 190  * intel_fb_obj_flush - flush frontbuffer object
 191  * @obj: GEM object to flush
 192  * @retire: set when retiring asynchronous rendering
 193  *
 194  * This function gets called every time rendering on the given object has
 195  * completed and frontbuffer caching can be started again. If @retire is true
 196  * then any delayed flushes will be unblocked.
 197  */
 198 void intel_fb_obj_flush(struct drm_i915_gem_object *obj,
 199                         bool retire)
 200 {
 201         struct drm_device *dev = obj->base.dev;
 202         struct drm_i915_private *dev_priv = dev->dev_private;
 203         unsigned frontbuffer_bits;
 204
 205         WARN_ON(!mutex_is_locked(&dev->struct_mutex));
 206
 207         if (!obj->frontbuffer_bits)
 208                 return;
 209
 210         frontbuffer_bits = obj->frontbuffer_bits;
 211
 212         if (retire) {
 213                 mutex_lock(&dev_priv->fb_tracking.lock);
 214                 /* Filter out new bits since rendering started. */
 215                 frontbuffer_bits &= dev_priv->fb_tracking.busy_bits;
 216
 217                 dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
 218                 mutex_unlock(&dev_priv->fb_tracking.lock);
 219         }
 220
 221         intel_frontbuffer_flush(dev, frontbuffer_bits);
 222 }
 223
 224 /**
 225  * intel_frontbuffer_flip_prepare - prepare asynchronous frontbuffer flip
 226  * @dev: DRM device
 227  * @frontbuffer_bits: frontbuffer plane tracking bits
 228  *
 229  * This function gets called after scheduling a flip on @obj. The actual
 230  * frontbuffer flushing will be delayed until completion is signalled with
 231  * intel_frontbuffer_flip_complete. If an invalidate happens in between this
 232  * flush will be cancelled.
 233  *
 234  * Can be called without any locks held.
 235  */
 236 void intel_frontbuffer_flip_prepare(struct drm_device *dev,
 237                                     unsigned frontbuffer_bits)
 238 {
 239         struct drm_i915_private *dev_priv = dev->dev_private;
 240
 241         mutex_lock(&dev_priv->fb_tracking.lock);
 242         dev_priv->fb_tracking.flip_bits |= frontbuffer_bits;
 243         /* Remove stale busy bits due to the old buffer. */
 244         dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
 245         mutex_unlock(&dev_priv->fb_tracking.lock);
 246
 247         intel_psr_single_frame_update(dev);
 248 }
 249
 250 /**
 251  * intel_frontbuffer_flip_complete - complete asynchronous frontbuffer flip
 252  * @dev: DRM device
 253  * @frontbuffer_bits: frontbuffer plane tracking bits
 254  *
 255  * This function gets called after the flip has been latched and will complete
 256  * on the next vblank. It will execute the flush if it hasn't been cancelled yet.
 257  *
 258  * Can be called without any locks held.
 259  */
 260 void intel_frontbuffer_flip_complete(struct drm_device *dev,
 261                                      unsigned frontbuffer_bits)
 262 {
 263         struct drm_i915_private *dev_priv = dev->dev_private;
 264
 265         mutex_lock(&dev_priv->fb_tracking.lock);
 266         /* Mask any cancelled flips. */
 267         frontbuffer_bits &= dev_priv->fb_tracking.flip_bits;
 268         dev_priv->fb_tracking.flip_bits &= ~frontbuffer_bits;
 269         mutex_unlock(&dev_priv->fb_tracking.lock);
 270
 271         intel_frontbuffer_flush(dev, frontbuffer_bits);
 272 }