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21 * DEALINGS IN THE SOFTWARE.
24 * Daniel Vetter <daniel.vetter@ffwll.ch>
28 * DOC: frontbuffer tracking
30 * Many features require us to track changes to the currently active
31 * frontbuffer, especially rendering targeted at the frontbuffer.
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
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
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.
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.
65 #include "intel_drv.h"
68 static void intel_increase_pllclock(struct drm_device
*dev
,
71 struct drm_i915_private
*dev_priv
= dev
->dev_private
;
72 int dpll_reg
= DPLL(pipe
);
75 if (!HAS_GMCH_DISPLAY(dev
))
78 if (!dev_priv
->lvds_downclock_avail
)
81 dpll
= I915_READ(dpll_reg
);
82 if (!HAS_PIPE_CXSR(dev
) && (dpll
& DISPLAY_RATE_SELECT_FPA1
)) {
83 DRM_DEBUG_DRIVER("upclocking LVDS\n");
85 assert_panel_unlocked(dev_priv
, pipe
);
87 dpll
&= ~DISPLAY_RATE_SELECT_FPA1
;
88 I915_WRITE(dpll_reg
, dpll
);
89 intel_wait_for_vblank(dev
, pipe
);
91 dpll
= I915_READ(dpll_reg
);
92 if (dpll
& DISPLAY_RATE_SELECT_FPA1
)
93 DRM_DEBUG_DRIVER("failed to upclock LVDS!\n");
98 * intel_mark_fb_busy - mark given planes as busy
100 * @frontbuffer_bits: bits for the affected planes
101 * @ring: optional ring for asynchronous commands
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.
106 static void intel_mark_fb_busy(struct drm_device
*dev
,
107 unsigned frontbuffer_bits
,
108 struct intel_engine_cs
*ring
)
110 struct drm_i915_private
*dev_priv
= dev
->dev_private
;
116 for_each_pipe(dev_priv
, pipe
) {
117 if (!(frontbuffer_bits
& INTEL_FRONTBUFFER_ALL_MASK(pipe
)))
120 intel_increase_pllclock(dev
, pipe
);
121 if (ring
&& intel_fbc_enabled(dev
))
122 ring
->fbc_dirty
= true;
127 * intel_fb_obj_invalidate - invalidate frontbuffer object
128 * @obj: GEM object to invalidate
129 * @ring: set for asynchronous rendering
131 * This function gets called every time rendering on the given object starts and
132 * frontbuffer caching (fbc, low refresh rate for DRRS, panel self refresh) must
133 * be invalidated. If @ring is non-NULL any subsequent invalidation will be delayed
134 * until the rendering completes or a flip on this frontbuffer plane is
137 void intel_fb_obj_invalidate(struct drm_i915_gem_object
*obj
,
138 struct intel_engine_cs
*ring
)
140 struct drm_device
*dev
= obj
->base
.dev
;
141 struct drm_i915_private
*dev_priv
= dev
->dev_private
;
143 WARN_ON(!mutex_is_locked(&dev
->struct_mutex
));
145 if (!obj
->frontbuffer_bits
)
149 mutex_lock(&dev_priv
->fb_tracking
.lock
);
150 dev_priv
->fb_tracking
.busy_bits
151 |= obj
->frontbuffer_bits
;
152 dev_priv
->fb_tracking
.flip_bits
153 &= ~obj
->frontbuffer_bits
;
154 mutex_unlock(&dev_priv
->fb_tracking
.lock
);
157 intel_mark_fb_busy(dev
, obj
->frontbuffer_bits
, ring
);
159 intel_psr_invalidate(dev
, obj
->frontbuffer_bits
);
160 intel_edp_drrs_invalidate(dev
, obj
->frontbuffer_bits
);
164 * intel_frontbuffer_flush - flush frontbuffer
166 * @frontbuffer_bits: frontbuffer plane tracking bits
168 * This function gets called every time rendering on the given planes has
169 * completed and frontbuffer caching can be started again. Flushes will get
170 * delayed if they're blocked by some outstanding asynchronous rendering.
172 * Can be called without any locks held.
174 void intel_frontbuffer_flush(struct drm_device
*dev
,
175 unsigned frontbuffer_bits
)
177 struct drm_i915_private
*dev_priv
= dev
->dev_private
;
179 /* Delay flushing when rings are still busy.*/
180 mutex_lock(&dev_priv
->fb_tracking
.lock
);
181 frontbuffer_bits
&= ~dev_priv
->fb_tracking
.busy_bits
;
182 mutex_unlock(&dev_priv
->fb_tracking
.lock
);
184 intel_mark_fb_busy(dev
, frontbuffer_bits
, NULL
);
186 intel_edp_drrs_flush(dev
, frontbuffer_bits
);
187 intel_psr_flush(dev
, frontbuffer_bits
);
190 * FIXME: Unconditional fbc flushing here is a rather gross hack and
191 * needs to be reworked into a proper frontbuffer tracking scheme like
194 if (dev_priv
->fbc
.need_sw_cache_clean
) {
195 dev_priv
->fbc
.need_sw_cache_clean
= false;
196 bdw_fbc_sw_flush(dev
, FBC_REND_CACHE_CLEAN
);
201 * intel_fb_obj_flush - flush frontbuffer object
202 * @obj: GEM object to flush
203 * @retire: set when retiring asynchronous rendering
205 * This function gets called every time rendering on the given object has
206 * completed and frontbuffer caching can be started again. If @retire is true
207 * then any delayed flushes will be unblocked.
209 void intel_fb_obj_flush(struct drm_i915_gem_object
*obj
,
212 struct drm_device
*dev
= obj
->base
.dev
;
213 struct drm_i915_private
*dev_priv
= dev
->dev_private
;
214 unsigned frontbuffer_bits
;
216 WARN_ON(!mutex_is_locked(&dev
->struct_mutex
));
218 if (!obj
->frontbuffer_bits
)
221 frontbuffer_bits
= obj
->frontbuffer_bits
;
224 mutex_lock(&dev_priv
->fb_tracking
.lock
);
225 /* Filter out new bits since rendering started. */
226 frontbuffer_bits
&= dev_priv
->fb_tracking
.busy_bits
;
228 dev_priv
->fb_tracking
.busy_bits
&= ~frontbuffer_bits
;
229 mutex_unlock(&dev_priv
->fb_tracking
.lock
);
232 intel_frontbuffer_flush(dev
, frontbuffer_bits
);
236 * intel_frontbuffer_flip_prepare - prepare asynchronous frontbuffer flip
238 * @frontbuffer_bits: frontbuffer plane tracking bits
240 * This function gets called after scheduling a flip on @obj. The actual
241 * frontbuffer flushing will be delayed until completion is signalled with
242 * intel_frontbuffer_flip_complete. If an invalidate happens in between this
243 * flush will be cancelled.
245 * Can be called without any locks held.
247 void intel_frontbuffer_flip_prepare(struct drm_device
*dev
,
248 unsigned frontbuffer_bits
)
250 struct drm_i915_private
*dev_priv
= dev
->dev_private
;
252 mutex_lock(&dev_priv
->fb_tracking
.lock
);
253 dev_priv
->fb_tracking
.flip_bits
|= frontbuffer_bits
;
254 /* Remove stale busy bits due to the old buffer. */
255 dev_priv
->fb_tracking
.busy_bits
&= ~frontbuffer_bits
;
256 mutex_unlock(&dev_priv
->fb_tracking
.lock
);
260 * intel_frontbuffer_flip_complete - complete asynchronous frontbuffer flip
262 * @frontbuffer_bits: frontbuffer plane tracking bits
264 * This function gets called after the flip has been latched and will complete
265 * on the next vblank. It will execute the flush if it hasn't been cancelled yet.
267 * Can be called without any locks held.
269 void intel_frontbuffer_flip_complete(struct drm_device
*dev
,
270 unsigned frontbuffer_bits
)
272 struct drm_i915_private
*dev_priv
= dev
->dev_private
;
274 mutex_lock(&dev_priv
->fb_tracking
.lock
);
275 /* Mask any cancelled flips. */
276 frontbuffer_bits
&= dev_priv
->fb_tracking
.flip_bits
;
277 dev_priv
->fb_tracking
.flip_bits
&= ~frontbuffer_bits
;
278 mutex_unlock(&dev_priv
->fb_tracking
.lock
);
280 intel_frontbuffer_flush(dev
, frontbuffer_bits
);
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