2 * Copyright (C) 2015 The Android Open Source Project
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 #define ATRACE_TAG ATRACE_TAG_GRAPHICS
18 #define LOG_TAG "hwcomposer-drm"
20 #include "drmhwcomposer.h"
21 #include "drmeventlistener.h"
22 #include "drmresources.h"
24 #include "virtualcompositorworker.h"
25 #include "vsyncworker.h"
37 #include <sys/param.h>
38 #include <sys/resource.h>
40 #include <xf86drmMode.h>
42 #include <cutils/log.h>
43 #include <cutils/properties.h>
44 #include <hardware/hardware.h>
45 #include <hardware/hwcomposer.h>
47 #include <sync/sync.h>
48 #include <utils/Trace.h>
50 #define UM_PER_INCH 25400
54 class DummySwSyncTimeline {
57 int ret = timeline_fd_.Set(sw_sync_timeline_create());
63 UniqueFd CreateDummyFence() {
64 int ret = sw_sync_fence_create(timeline_fd_.get(), "dummy fence",
67 ALOGE("Failed to create dummy fence %d", ret);
73 ret = sw_sync_timeline_inc(timeline_fd_.get(), 1);
75 ALOGE("Failed to increment dummy sync timeline %d", ret);
84 UniqueFd timeline_fd_;
88 struct CheckedOutputFd {
89 CheckedOutputFd(int *fd, const char *description,
90 DummySwSyncTimeline &timeline)
91 : fd_(fd), description_(description), timeline_(timeline) {
93 CheckedOutputFd(CheckedOutputFd &&rhs)
94 : description_(rhs.description_), timeline_(rhs.timeline_) {
95 std::swap(fd_, rhs.fd_);
98 CheckedOutputFd &operator=(const CheckedOutputFd &rhs) = delete;
107 *fd_ = timeline_.CreateDummyFence().Release();
110 ALOGE("Failed to fill %s (%p == %d) before destruction",
111 description_.c_str(), fd_, *fd_);
116 std::string description_;
117 DummySwSyncTimeline &timeline_;
120 typedef struct hwc_drm_display {
121 struct hwc_context_t *ctx;
124 std::vector<uint32_t> config_ids;
126 VSyncWorker vsync_worker;
129 class DrmHotplugHandler : public DrmEventHandler {
131 void Init(DrmResources *drm, const struct hwc_procs *procs) {
136 void HandleEvent(uint64_t timestamp_us) {
137 for (auto &conn : drm_->connectors()) {
138 drmModeConnection old_state = conn->state();
142 drmModeConnection cur_state = conn->state();
144 if (cur_state == old_state)
147 ALOGI("%s event @%" PRIu64 " for connector %u\n",
148 cur_state == DRM_MODE_CONNECTED ? "Plug" : "Unplug", timestamp_us,
151 if (cur_state == DRM_MODE_CONNECTED) {
152 // Take the first one, then look for the preferred
153 DrmMode mode = *(conn->modes().begin());
154 for (auto &m : conn->modes()) {
155 if (m.type() & DRM_MODE_TYPE_PREFERRED) {
160 ALOGI("Setting mode %dx%d for connector %d\n", mode.h_display(),
161 mode.v_display(), conn->id());
162 int ret = drm_->SetDisplayActiveMode(conn->display(), mode);
164 ALOGE("Failed to set active config %d", ret);
168 int ret = drm_->SetDpmsMode(conn->display(), DRM_MODE_DPMS_OFF);
170 ALOGE("Failed to set dpms mode off %d", ret);
175 procs_->hotplug(procs_, conn->display(),
176 cur_state == DRM_MODE_CONNECTED ? 1 : 0);
181 DrmResources *drm_ = NULL;
182 const struct hwc_procs *procs_ = NULL;
185 struct hwc_context_t {
186 // map of display:hwc_drm_display_t
187 typedef std::map<int, hwc_drm_display_t> DisplayMap;
190 virtual_compositor_worker.Exit();
193 hwc_composer_device_1_t device;
194 hwc_procs_t const *procs = NULL;
198 std::unique_ptr<Importer> importer;
199 const gralloc_module_t *gralloc;
200 DummySwSyncTimeline dummy_timeline;
201 VirtualCompositorWorker virtual_compositor_worker;
202 DrmHotplugHandler hotplug_handler;
205 class DrmVsyncCallback : public VsyncCallback {
207 DrmVsyncCallback(hwc_procs_t const *procs) : procs_(procs) {
210 void Callback(int display, int64_t timestamp) {
211 procs_->vsync(procs_, display, timestamp);
214 hwc_procs_t const *procs_;
217 static void hwc_dump(struct hwc_composer_device_1 *dev, char *buff,
219 struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
220 std::ostringstream out;
222 ctx->drm.compositor()->Dump(&out);
223 std::string out_str = out.str();
224 strncpy(buff, out_str.c_str(),
225 std::min((size_t)buff_len, out_str.length() + 1));
226 buff[buff_len - 1] = '\0';
229 static bool hwc_skip_layer(const std::pair<int, int> &indices, int i) {
230 return indices.first >= 0 && i >= indices.first && i <= indices.second;
233 static int hwc_prepare(hwc_composer_device_1_t *dev, size_t num_displays,
234 hwc_display_contents_1_t **display_contents) {
235 struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
237 for (int i = 0; i < (int)num_displays; ++i) {
238 if (!display_contents[i])
241 bool use_framebuffer_target = false;
243 if (i == HWC_DISPLAY_VIRTUAL) {
244 use_framebuffer_target = true;
246 DrmConnector *c = ctx->drm.GetConnectorForDisplay(i);
248 ALOGE("Failed to get DrmConnector for display %d", i);
251 mode = c->active_mode();
254 // Since we can't composite HWC_SKIP_LAYERs by ourselves, we'll let SF
255 // handle all layers in between the first and last skip layers. So find the
256 // outer indices and mark everything in between as HWC_FRAMEBUFFER
257 std::pair<int, int> skip_layer_indices(-1, -1);
258 int num_layers = display_contents[i]->numHwLayers;
259 for (int j = 0; !use_framebuffer_target && j < num_layers; ++j) {
260 hwc_layer_1_t *layer = &display_contents[i]->hwLayers[j];
262 if (!(layer->flags & HWC_SKIP_LAYER))
265 if (skip_layer_indices.first == -1)
266 skip_layer_indices.first = j;
267 skip_layer_indices.second = j;
270 for (int j = 0; j < num_layers; ++j) {
271 hwc_layer_1_t *layer = &display_contents[i]->hwLayers[j];
273 if (!use_framebuffer_target && !hwc_skip_layer(skip_layer_indices, j)) {
274 // If the layer is off the screen, don't earmark it for an overlay.
275 // We'll leave it as-is, which effectively just drops it from the frame
276 const hwc_rect_t *frame = &layer->displayFrame;
277 if ((frame->right - frame->left) <= 0 ||
278 (frame->bottom - frame->top) <= 0 ||
279 frame->right <= 0 || frame->bottom <= 0 ||
280 frame->left >= (int)mode.h_display() ||
281 frame->top >= (int)mode.v_display())
284 if (layer->compositionType == HWC_FRAMEBUFFER)
285 layer->compositionType = HWC_OVERLAY;
287 switch (layer->compositionType) {
291 case HWC_CURSOR_OVERLAY:
292 layer->compositionType = HWC_FRAMEBUFFER;
302 static void hwc_add_layer_to_retire_fence(
303 hwc_layer_1_t *layer, hwc_display_contents_1_t *display_contents) {
304 if (layer->releaseFenceFd < 0)
307 if (display_contents->retireFenceFd >= 0) {
308 int old_retire_fence = display_contents->retireFenceFd;
309 display_contents->retireFenceFd =
310 sync_merge("dc_retire", old_retire_fence, layer->releaseFenceFd);
311 close(old_retire_fence);
313 display_contents->retireFenceFd = dup(layer->releaseFenceFd);
317 static int hwc_set(hwc_composer_device_1_t *dev, size_t num_displays,
318 hwc_display_contents_1_t **sf_display_contents) {
320 struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
323 std::vector<CheckedOutputFd> checked_output_fences;
324 std::vector<DrmHwcDisplayContents> displays_contents;
325 std::vector<DrmCompositionDisplayLayersMap> layers_map;
326 std::vector<std::vector<size_t>> layers_indices;
327 displays_contents.reserve(num_displays);
328 // layers_map.reserve(num_displays);
329 layers_indices.reserve(num_displays);
331 // Phase one does nothing that would cause errors. Only take ownership of FDs.
332 for (size_t i = 0; i < num_displays; ++i) {
333 hwc_display_contents_1_t *dc = sf_display_contents[i];
334 displays_contents.emplace_back();
335 DrmHwcDisplayContents &display_contents = displays_contents.back();
336 layers_indices.emplace_back();
337 std::vector<size_t> &indices_to_composite = layers_indices.back();
339 if (!sf_display_contents[i])
342 if (i == HWC_DISPLAY_VIRTUAL) {
343 ctx->virtual_compositor_worker.QueueComposite(dc);
347 std::ostringstream display_index_formatter;
348 display_index_formatter << "retire fence for display " << i;
349 std::string display_fence_description(display_index_formatter.str());
350 checked_output_fences.emplace_back(&dc->retireFenceFd,
351 display_fence_description.c_str(),
352 ctx->dummy_timeline);
353 display_contents.retire_fence = OutputFd(&dc->retireFenceFd);
355 size_t num_dc_layers = dc->numHwLayers;
356 int framebuffer_target_index = -1;
357 for (size_t j = 0; j < num_dc_layers; ++j) {
358 hwc_layer_1_t *sf_layer = &dc->hwLayers[j];
359 if (sf_layer->compositionType == HWC_FRAMEBUFFER_TARGET) {
360 framebuffer_target_index = j;
365 for (size_t j = 0; j < num_dc_layers; ++j) {
366 hwc_layer_1_t *sf_layer = &dc->hwLayers[j];
368 display_contents.layers.emplace_back();
369 DrmHwcLayer &layer = display_contents.layers.back();
371 // In prepare() we marked all layers FRAMEBUFFER between SKIP_LAYER's.
372 // This means we should insert the FB_TARGET layer in the composition
373 // stack at the location of the first skip layer, and ignore the rest.
374 if (sf_layer->flags & HWC_SKIP_LAYER) {
375 if (framebuffer_target_index < 0)
377 int idx = framebuffer_target_index;
378 framebuffer_target_index = -1;
379 hwc_layer_1_t *fbt_layer = &dc->hwLayers[idx];
380 if (!fbt_layer->handle || (fbt_layer->flags & HWC_SKIP_LAYER)) {
381 ALOGE("Invalid HWC_FRAMEBUFFER_TARGET with HWC_SKIP_LAYER present");
384 indices_to_composite.push_back(idx);
388 if (sf_layer->compositionType == HWC_OVERLAY)
389 indices_to_composite.push_back(j);
391 layer.acquire_fence.Set(sf_layer->acquireFenceFd);
392 sf_layer->acquireFenceFd = -1;
394 std::ostringstream layer_fence_formatter;
395 layer_fence_formatter << "release fence for layer " << j << " of display "
397 std::string layer_fence_description(layer_fence_formatter.str());
398 checked_output_fences.emplace_back(&sf_layer->releaseFenceFd,
399 layer_fence_description.c_str(),
400 ctx->dummy_timeline);
401 layer.release_fence = OutputFd(&sf_layer->releaseFenceFd);
404 // This is a catch-all in case we get a frame without any overlay layers, or
405 // skip layers, but with a value fb_target layer. This _shouldn't_ happen,
406 // but it's not ruled out by the hwc specification
407 if (indices_to_composite.empty() && framebuffer_target_index >= 0) {
408 hwc_layer_1_t *sf_layer = &dc->hwLayers[framebuffer_target_index];
409 if (!sf_layer->handle || (sf_layer->flags & HWC_SKIP_LAYER)) {
411 "Expected valid layer with HWC_FRAMEBUFFER_TARGET when all "
412 "HWC_OVERLAY layers are skipped.");
415 indices_to_composite.push_back(framebuffer_target_index);
422 for (size_t i = 0; i < num_displays; ++i) {
423 hwc_display_contents_1_t *dc = sf_display_contents[i];
424 DrmHwcDisplayContents &display_contents = displays_contents[i];
425 if (!sf_display_contents[i] || i == HWC_DISPLAY_VIRTUAL)
428 layers_map.emplace_back();
429 DrmCompositionDisplayLayersMap &map = layers_map.back();
431 map.geometry_changed =
432 (dc->flags & HWC_GEOMETRY_CHANGED) == HWC_GEOMETRY_CHANGED;
433 std::vector<size_t> &indices_to_composite = layers_indices[i];
434 for (size_t j : indices_to_composite) {
435 hwc_layer_1_t *sf_layer = &dc->hwLayers[j];
437 DrmHwcLayer &layer = display_contents.layers[j];
439 ret = layer.InitFromHwcLayer(sf_layer, ctx->importer.get(), ctx->gralloc);
441 ALOGE("Failed to init composition from layer %d", ret);
444 map.layers.emplace_back(std::move(layer));
448 std::unique_ptr<DrmComposition> composition(
449 ctx->drm.compositor()->CreateComposition(ctx->importer.get()));
451 ALOGE("Drm composition init failed");
455 ret = composition->SetLayers(layers_map.size(), layers_map.data());
460 ret = ctx->drm.compositor()->QueueComposition(std::move(composition));
465 for (size_t i = 0; i < num_displays; ++i) {
466 hwc_display_contents_1_t *dc = sf_display_contents[i];
470 size_t num_dc_layers = dc->numHwLayers;
471 for (size_t j = 0; j < num_dc_layers; ++j) {
472 hwc_layer_1_t *layer = &dc->hwLayers[j];
473 if (layer->flags & HWC_SKIP_LAYER)
475 hwc_add_layer_to_retire_fence(layer, dc);
479 composition.reset(NULL);
484 static int hwc_event_control(struct hwc_composer_device_1 *dev, int display,
485 int event, int enabled) {
486 if (event != HWC_EVENT_VSYNC || (enabled != 0 && enabled != 1))
489 struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
490 hwc_drm_display_t *hd = &ctx->displays[display];
491 hd->vsync_worker.VSyncControl(enabled);
495 static int hwc_set_power_mode(struct hwc_composer_device_1 *dev, int display,
497 struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
499 uint64_t dpmsValue = 0;
501 case HWC_POWER_MODE_OFF:
502 dpmsValue = DRM_MODE_DPMS_OFF;
505 /* We can't support dozing right now, so go full on */
506 case HWC_POWER_MODE_DOZE:
507 case HWC_POWER_MODE_DOZE_SUSPEND:
508 case HWC_POWER_MODE_NORMAL:
509 dpmsValue = DRM_MODE_DPMS_ON;
512 return ctx->drm.SetDpmsMode(display, dpmsValue);
515 static int hwc_query(struct hwc_composer_device_1 * /* dev */, int what,
518 case HWC_BACKGROUND_LAYER_SUPPORTED:
519 *value = 0; /* TODO: We should do this */
521 case HWC_VSYNC_PERIOD:
522 ALOGW("Query for deprecated vsync value, returning 60Hz");
523 *value = 1000 * 1000 * 1000 / 60;
525 case HWC_DISPLAY_TYPES_SUPPORTED:
526 *value = HWC_DISPLAY_PRIMARY_BIT | HWC_DISPLAY_EXTERNAL_BIT |
527 HWC_DISPLAY_VIRTUAL_BIT;
533 static void hwc_register_procs(struct hwc_composer_device_1 *dev,
534 hwc_procs_t const *procs) {
535 struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
539 for (std::pair<const int, hwc_drm_display> &display_entry : ctx->displays) {
540 auto callback = std::make_shared<DrmVsyncCallback>(procs);
541 display_entry.second.vsync_worker.RegisterCallback(std::move(callback));
544 ctx->hotplug_handler.Init(&ctx->drm, procs);
545 ctx->drm.event_listener()->RegisterHotplugHandler(&ctx->hotplug_handler);
548 static int hwc_get_display_configs(struct hwc_composer_device_1 *dev,
549 int display, uint32_t *configs,
550 size_t *num_configs) {
554 struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
555 hwc_drm_display_t *hd = &ctx->displays[display];
556 hd->config_ids.clear();
558 DrmConnector *connector = ctx->drm.GetConnectorForDisplay(display);
560 ALOGE("Failed to get connector for display %d", display);
564 int ret = connector->UpdateModes();
566 ALOGE("Failed to update display modes %d", ret);
570 for (const DrmMode &mode : connector->modes()) {
571 size_t idx = hd->config_ids.size();
572 if (idx == *num_configs)
574 hd->config_ids.push_back(mode.id());
575 configs[idx] = mode.id();
577 *num_configs = hd->config_ids.size();
578 return *num_configs == 0 ? -1 : 0;
581 static int hwc_get_display_attributes(struct hwc_composer_device_1 *dev,
582 int display, uint32_t config,
583 const uint32_t *attributes,
585 struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
586 DrmConnector *c = ctx->drm.GetConnectorForDisplay(display);
588 ALOGE("Failed to get DrmConnector for display %d", display);
592 for (const DrmMode &conn_mode : c->modes()) {
593 if (conn_mode.id() == config) {
598 if (mode.id() == 0) {
599 ALOGE("Failed to find active mode for display %d", display);
603 uint32_t mm_width = c->mm_width();
604 uint32_t mm_height = c->mm_height();
605 for (int i = 0; attributes[i] != HWC_DISPLAY_NO_ATTRIBUTE; ++i) {
606 switch (attributes[i]) {
607 case HWC_DISPLAY_VSYNC_PERIOD:
608 values[i] = 1000 * 1000 * 1000 / mode.v_refresh();
610 case HWC_DISPLAY_WIDTH:
611 values[i] = mode.h_display();
613 case HWC_DISPLAY_HEIGHT:
614 values[i] = mode.v_display();
616 case HWC_DISPLAY_DPI_X:
617 /* Dots per 1000 inches */
618 values[i] = mm_width ? (mode.h_display() * UM_PER_INCH) / mm_width : 0;
620 case HWC_DISPLAY_DPI_Y:
621 /* Dots per 1000 inches */
623 mm_height ? (mode.v_display() * UM_PER_INCH) / mm_height : 0;
630 static int hwc_get_active_config(struct hwc_composer_device_1 *dev,
632 struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
633 DrmConnector *c = ctx->drm.GetConnectorForDisplay(display);
635 ALOGE("Failed to get DrmConnector for display %d", display);
639 DrmMode mode = c->active_mode();
640 hwc_drm_display_t *hd = &ctx->displays[display];
641 for (size_t i = 0; i < hd->config_ids.size(); ++i) {
642 if (hd->config_ids[i] == mode.id())
648 static int hwc_set_active_config(struct hwc_composer_device_1 *dev, int display,
650 struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
651 hwc_drm_display_t *hd = &ctx->displays[display];
652 if (index >= (int)hd->config_ids.size()) {
653 ALOGE("Invalid config index %d passed in", index);
657 DrmConnector *c = ctx->drm.GetConnectorForDisplay(display);
659 ALOGE("Failed to get connector for display %d", display);
663 if (c->state() != DRM_MODE_CONNECTED)
667 for (const DrmMode &conn_mode : c->modes()) {
668 if (conn_mode.id() == hd->config_ids[index]) {
673 if (mode.id() != hd->config_ids[index]) {
674 ALOGE("Could not find active mode for %d/%d", index, hd->config_ids[index]);
677 int ret = ctx->drm.SetDisplayActiveMode(display, mode);
679 ALOGE("Failed to set active config %d", ret);
682 ret = ctx->drm.SetDpmsMode(display, DRM_MODE_DPMS_ON);
684 ALOGE("Failed to set dpms mode on %d", ret);
690 static int hwc_device_close(struct hw_device_t *dev) {
691 struct hwc_context_t *ctx = (struct hwc_context_t *)dev;
697 * TODO: This function sets the active config to the first one in the list. This
698 * should be fixed such that it selects the preferred mode for the display, or
699 * some other, saner, method of choosing the config.
701 static int hwc_set_initial_config(hwc_drm_display_t *hd) {
703 size_t num_configs = 1;
704 int ret = hwc_get_display_configs(&hd->ctx->device, hd->display, &config,
706 if (ret || !num_configs)
709 ret = hwc_set_active_config(&hd->ctx->device, hd->display, 0);
711 ALOGE("Failed to set active config d=%d ret=%d", hd->display, ret);
718 static int hwc_initialize_display(struct hwc_context_t *ctx, int display) {
719 hwc_drm_display_t *hd = &ctx->displays[display];
721 hd->display = display;
723 int ret = hwc_set_initial_config(hd);
725 ALOGE("Failed to set initial config for d=%d ret=%d", display, ret);
729 ret = hd->vsync_worker.Init(&ctx->drm, display);
731 ALOGE("Failed to create event worker for display %d %d\n", display, ret);
738 static int hwc_enumerate_displays(struct hwc_context_t *ctx) {
740 for (auto &conn : ctx->drm.connectors()) {
741 ret = hwc_initialize_display(ctx, conn->display());
743 ALOGE("Failed to initialize display %d", conn->display());
748 ret = ctx->virtual_compositor_worker.Init();
750 ALOGE("Failed to initialize virtual compositor worker");
756 static int hwc_device_open(const struct hw_module_t *module, const char *name,
757 struct hw_device_t **dev) {
758 if (strcmp(name, HWC_HARDWARE_COMPOSER)) {
759 ALOGE("Invalid module name- %s", name);
763 std::unique_ptr<hwc_context_t> ctx(new hwc_context_t());
765 ALOGE("Failed to allocate hwc context");
769 int ret = ctx->drm.Init();
771 ALOGE("Can't initialize Drm object %d", ret);
775 ret = hw_get_module(GRALLOC_HARDWARE_MODULE_ID,
776 (const hw_module_t **)&ctx->gralloc);
778 ALOGE("Failed to open gralloc module %d", ret);
782 ret = ctx->dummy_timeline.Init();
784 ALOGE("Failed to create dummy sw sync timeline %d", ret);
788 ctx->importer.reset(Importer::CreateInstance(&ctx->drm));
789 if (!ctx->importer) {
790 ALOGE("Failed to create importer instance");
794 ret = hwc_enumerate_displays(ctx.get());
796 ALOGE("Failed to enumerate displays: %s", strerror(ret));
800 ctx->device.common.tag = HARDWARE_DEVICE_TAG;
801 ctx->device.common.version = HWC_DEVICE_API_VERSION_1_4;
802 ctx->device.common.module = const_cast<hw_module_t *>(module);
803 ctx->device.common.close = hwc_device_close;
805 ctx->device.dump = hwc_dump;
806 ctx->device.prepare = hwc_prepare;
807 ctx->device.set = hwc_set;
808 ctx->device.eventControl = hwc_event_control;
809 ctx->device.setPowerMode = hwc_set_power_mode;
810 ctx->device.query = hwc_query;
811 ctx->device.registerProcs = hwc_register_procs;
812 ctx->device.getDisplayConfigs = hwc_get_display_configs;
813 ctx->device.getDisplayAttributes = hwc_get_display_attributes;
814 ctx->device.getActiveConfig = hwc_get_active_config;
815 ctx->device.setActiveConfig = hwc_set_active_config;
816 ctx->device.setCursorPositionAsync = NULL; /* TODO: Add cursor */
818 *dev = &ctx->device.common;
825 static struct hw_module_methods_t hwc_module_methods = {
826 .open = android::hwc_device_open
829 hwc_module_t HAL_MODULE_INFO_SYM = {
831 .tag = HARDWARE_MODULE_TAG,
834 .id = HWC_HARDWARE_MODULE_ID,
835 .name = "DRM hwcomposer module",
836 .author = "The Android Open Source Project",
837 .methods = &hwc_module_methods,