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 "intel_frontbuffer.h"
  67 #include "i915_drv.h"
  68
  69 void __intel_fb_obj_invalidate(struct drm_i915_gem_object *obj,
  70                                enum fb_op_origin origin,
  71                                unsigned int frontbuffer_bits)
  72 {
  73         struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
  74
  75         if (origin == ORIGIN_CS) {
  76                 spin_lock(&dev_priv->fb_tracking.lock);
  77                 dev_priv->fb_tracking.busy_bits |= frontbuffer_bits;
  78                 dev_priv->fb_tracking.flip_bits &= ~frontbuffer_bits;
  79                 spin_unlock(&dev_priv->fb_tracking.lock);
  80         }
  81
  82         might_sleep();
  83         intel_psr_invalidate(dev_priv, frontbuffer_bits, origin);
  84         intel_edp_drrs_invalidate(dev_priv, frontbuffer_bits);
  85         intel_fbc_invalidate(dev_priv, frontbuffer_bits, origin);
  86 }
  87
  88 /**
  89  * intel_frontbuffer_flush - flush frontbuffer
  90  * @dev_priv: i915 device
  91  * @frontbuffer_bits: frontbuffer plane tracking bits
  92  * @origin: which operation caused the flush
  93  *
  94  * This function gets called every time rendering on the given planes has
  95  * completed and frontbuffer caching can be started again. Flushes will get
  96  * delayed if they're blocked by some outstanding asynchronous rendering.
  97  *
  98  * Can be called without any locks held.
  99  */
 100 static void intel_frontbuffer_flush(struct drm_i915_private *dev_priv,
 101                                     unsigned frontbuffer_bits,
 102                                     enum fb_op_origin origin)
 103 {
 104         /* Delay flushing when rings are still busy.*/
 105         spin_lock(&dev_priv->fb_tracking.lock);
 106         frontbuffer_bits &= ~dev_priv->fb_tracking.busy_bits;
 107         spin_unlock(&dev_priv->fb_tracking.lock);
 108
 109         if (!frontbuffer_bits)
 110                 return;
 111
 112         might_sleep();
 113         intel_edp_drrs_flush(dev_priv, frontbuffer_bits);
 114         intel_psr_flush(dev_priv, frontbuffer_bits, origin);
 115         intel_fbc_flush(dev_priv, frontbuffer_bits, origin);
 116 }
 117
 118 void __intel_fb_obj_flush(struct drm_i915_gem_object *obj,
 119                           enum fb_op_origin origin,
 120                           unsigned int frontbuffer_bits)
 121 {
 122         struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
 123
 124         if (origin == ORIGIN_CS) {
 125                 spin_lock(&dev_priv->fb_tracking.lock);
 126                 /* Filter out new bits since rendering started. */
 127                 frontbuffer_bits &= dev_priv->fb_tracking.busy_bits;
 128                 dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
 129                 spin_unlock(&dev_priv->fb_tracking.lock);
 130         }
 131
 132         if (frontbuffer_bits)
 133                 intel_frontbuffer_flush(dev_priv, frontbuffer_bits, origin);
 134 }
 135
 136 /**
 137  * intel_frontbuffer_flip_prepare - prepare asynchronous frontbuffer flip
 138  * @dev_priv: i915 device
 139  * @frontbuffer_bits: frontbuffer plane tracking bits
 140  *
 141  * This function gets called after scheduling a flip on @obj. The actual
 142  * frontbuffer flushing will be delayed until completion is signalled with
 143  * intel_frontbuffer_flip_complete. If an invalidate happens in between this
 144  * flush will be cancelled.
 145  *
 146  * Can be called without any locks held.
 147  */
 148 void intel_frontbuffer_flip_prepare(struct drm_i915_private *dev_priv,
 149                                     unsigned frontbuffer_bits)
 150 {
 151         spin_lock(&dev_priv->fb_tracking.lock);
 152         dev_priv->fb_tracking.flip_bits |= frontbuffer_bits;
 153         /* Remove stale busy bits due to the old buffer. */
 154         dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
 155         spin_unlock(&dev_priv->fb_tracking.lock);
 156 }
 157
 158 /**
 159  * intel_frontbuffer_flip_complete - complete asynchronous frontbuffer flip
 160  * @dev_priv: i915 device
 161  * @frontbuffer_bits: frontbuffer plane tracking bits
 162  *
 163  * This function gets called after the flip has been latched and will complete
 164  * on the next vblank. It will execute the flush if it hasn't been cancelled yet.
 165  *
 166  * Can be called without any locks held.
 167  */
 168 void intel_frontbuffer_flip_complete(struct drm_i915_private *dev_priv,
 169                                      unsigned frontbuffer_bits)
 170 {
 171         spin_lock(&dev_priv->fb_tracking.lock);
 172         /* Mask any cancelled flips. */
 173         frontbuffer_bits &= dev_priv->fb_tracking.flip_bits;
 174         dev_priv->fb_tracking.flip_bits &= ~frontbuffer_bits;
 175         spin_unlock(&dev_priv->fb_tracking.lock);
 176
 177         if (frontbuffer_bits)
 178                 intel_frontbuffer_flush(dev_priv,
 179                                         frontbuffer_bits, ORIGIN_FLIP);
 180 }
 181
 182 /**
 183  * intel_frontbuffer_flip - synchronous frontbuffer flip
 184  * @dev_priv: i915 device
 185  * @frontbuffer_bits: frontbuffer plane tracking bits
 186  *
 187  * This function gets called after scheduling a flip on @obj. This is for
 188  * synchronous plane updates which will happen on the next vblank and which will
 189  * not get delayed by pending gpu rendering.
 190  *
 191  * Can be called without any locks held.
 192  */
 193 void intel_frontbuffer_flip(struct drm_i915_private *dev_priv,
 194                             unsigned frontbuffer_bits)
 195 {
 196         spin_lock(&dev_priv->fb_tracking.lock);
 197         /* Remove stale busy bits due to the old buffer. */
 198         dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
 199         spin_unlock(&dev_priv->fb_tracking.lock);
 200
 201         intel_frontbuffer_flush(dev_priv, frontbuffer_bits, ORIGIN_FLIP);
 202 }