SF: Propagate Display Mode Rejection from SF to DM

Create a new DisplayEventReceiver callback for onModeRejected
to signal mode rejection from SF to DM so that DM can trigger
a retry.
Add the plumbing through DisplayEventReceiver and EventThread

Bug: 374184110
Test: manual
Flag: com.android.graphics.surfaceflinger.flags.display_config_error_hal

Change-Id: I78515d413bdf2e6e07d6649b7b60df8ced199b19
Signed-off-by: Manasi Navare <navaremanasi@google.com>

Author: Manasi Navare

libs/gui/Choreographer.cpp

@@ -369,6 +369,10 @@ void Choreographer::dispatchHdcpLevelsChanged(PhysicalDisplayId displayId, int32
           this, to_string(displayId).c_str(), connectedLevel, maxLevel);
 }
 
+void Choreographer::dispatchModeRejected(PhysicalDisplayId, int32_t) {
+    LOG_ALWAYS_FATAL("dispatchModeRejected was called but was never registered");
+}
+
 void Choreographer::handleMessage(const Message& message) {
     switch (message.what) {
         case MSG_SCHEDULE_CALLBACKS:

libs/gui/DisplayEventDispatcher.cpp

@@ -211,6 +211,9 @@ bool DisplayEventDispatcher::processPendingEvents(nsecs_t* outTimestamp,
                                               ev.hdcpLevelsChange.connectedLevel,
                                               ev.hdcpLevelsChange.maxLevel);
                     break;
+                case DisplayEventReceiver::DISPLAY_EVENT_MODE_REJECTION:
+                    dispatchModeRejected(ev.header.displayId, ev.modeRejection.modeId);
+                    break;
                 default:
                     ALOGW("dispatcher %p ~ ignoring unknown event type %#x", this, ev.header.type);
                     break;

libs/gui/include/gui/Choreographer.h

@@ -127,6 +127,7 @@ class Choreographer : public DisplayEventDispatcher, public MessageHandler {
                                     std::vector<FrameRateOverride> overrides) override;
     void dispatchHdcpLevelsChanged(PhysicalDisplayId displayId, int32_t connectedLevel,
                                    int32_t maxLevel) override;
+    void dispatchModeRejected(PhysicalDisplayId displayId, int32_t modeId) override;
 
     void scheduleCallbacks();
 

libs/gui/include/gui/DisplayEventDispatcher.h

@@ -68,6 +68,8 @@ class DisplayEventDispatcher : public LooperCallback {
     virtual void dispatchHdcpLevelsChanged(PhysicalDisplayId displayId, int32_t connectedLevel,
                                            int32_t maxLevel) = 0;
 
+    virtual void dispatchModeRejected(PhysicalDisplayId displayId, int32_t modeId) = 0;
+
     bool processPendingEvents(nsecs_t* outTimestamp, PhysicalDisplayId* outDisplayId,
                               uint32_t* outCount, VsyncEventData* outVsyncEventData);
 

libs/gui/include/gui/DisplayEventReceiver.h

@@ -62,6 +62,7 @@ class DisplayEventReceiver {
         DISPLAY_EVENT_VSYNC = fourcc('v', 's', 'y', 'n'),
         DISPLAY_EVENT_HOTPLUG = fourcc('p', 'l', 'u', 'g'),
         DISPLAY_EVENT_MODE_CHANGE = fourcc('m', 'o', 'd', 'e'),
+        DISPLAY_EVENT_MODE_REJECTION = fourcc('r', 'e', 'j', 'e'),
         DISPLAY_EVENT_NULL = fourcc('n', 'u', 'l', 'l'),
         DISPLAY_EVENT_FRAME_RATE_OVERRIDE = fourcc('r', 'a', 't', 'e'),
         DISPLAY_EVENT_FRAME_RATE_OVERRIDE_FLUSH = fourcc('f', 'l', 's', 'h'),
@@ -96,6 +97,10 @@ class DisplayEventReceiver {
             nsecs_t vsyncPeriod __attribute__((aligned(8)));
         };
 
+        struct ModeRejection {
+            int32_t modeId;
+        };
+
         struct FrameRateOverride {
             uid_t uid __attribute__((aligned(8)));
             float frameRateHz __attribute__((aligned(8)));
@@ -117,6 +122,7 @@ class DisplayEventReceiver {
             ModeChange modeChange;
             FrameRateOverride frameRateOverride;
             HdcpLevelsChange hdcpLevelsChange;
+            ModeRejection modeRejection;
         };
     };
     static_assert(sizeof(Event) == 224);

services/surfaceflinger/Scheduler/EventThread.cpp

@@ -43,6 +43,7 @@
 #include <utils/Errors.h>
 
 #include <common/FlagManager.h>
+#include <scheduler/FrameRateMode.h>
 #include <scheduler/VsyncConfig.h>
 #include "FrameTimeline.h"
 #include "VSyncDispatch.h"
@@ -102,6 +103,10 @@ std::string toString(const DisplayEventReceiver::Event& event) {
                                 to_string(event.header.displayId).c_str(),
                                 event.hdcpLevelsChange.connectedLevel,
                                 event.hdcpLevelsChange.maxLevel);
+        case DisplayEventReceiver::DISPLAY_EVENT_MODE_REJECTION:
+            return StringPrintf("ModeRejected{displayId=%s, modeId=%u}",
+                                to_string(event.header.displayId).c_str(),
+                                event.modeRejection.modeId);
         default:
             return "Event{}";
     }
@@ -186,6 +191,18 @@ DisplayEventReceiver::Event makeHdcpLevelsChange(PhysicalDisplayId displayId,
     };
 }
 
+DisplayEventReceiver::Event makeModeRejection(PhysicalDisplayId displayId, DisplayModeId modeId) {
+    return DisplayEventReceiver::Event{
+            .header =
+                    DisplayEventReceiver::Event::Header{
+                            .type = DisplayEventReceiver::DISPLAY_EVENT_MODE_REJECTION,
+                            .displayId = displayId,
+                            .timestamp = systemTime(),
+                    },
+            .modeRejection.modeId = ftl::to_underlying(modeId),
+    };
+}
+
 } // namespace
 
 EventThreadConnection::EventThreadConnection(EventThread* eventThread, uid_t callingUid,
@@ -480,6 +497,13 @@ void EventThread::onHdcpLevelsChanged(PhysicalDisplayId displayId, int32_t conne
     mCondition.notify_all();
 }
 
+void EventThread::onModeRejected(PhysicalDisplayId displayId, DisplayModeId modeId) {
+    std::lock_guard<std::mutex> lock(mMutex);
+
+    mPendingEvents.push_back(makeModeRejection(displayId, modeId));
+    mCondition.notify_all();
+}
+
 // Merge lists of buffer stuffed Uids
 void EventThread::addBufferStuffedUids(BufferStuffingMap bufferStuffedUids) {
     std::lock_guard<std::mutex> lock(mMutex);

services/surfaceflinger/Scheduler/EventThread.h

@@ -21,6 +21,7 @@
 #include <gui/DisplayEventReceiver.h>
 #include <private/gui/BitTube.h>
 #include <sys/types.h>
+#include <ui/DisplayId.h>
 #include <utils/Errors.h>
 
 #include <scheduler/FrameRateMode.h>
@@ -32,6 +33,7 @@
 #include <thread>
 #include <vector>
 
+#include "DisplayHardware/DisplayMode.h"
 #include "TracedOrdinal.h"
 #include "VSyncDispatch.h"
 #include "VsyncSchedule.h"
@@ -115,6 +117,9 @@ class EventThread {
     // called when SF changes the active mode and apps needs to be notified about the change
     virtual void onModeChanged(const scheduler::FrameRateMode&) = 0;
 
+    // called when SF rejects the mode change request
+    virtual void onModeRejected(PhysicalDisplayId displayId, DisplayModeId modeId) = 0;
+
     // called when SF updates the Frame Rate Override list
     virtual void onFrameRateOverridesChanged(PhysicalDisplayId displayId,
                                              std::vector<FrameRateOverride> overrides) = 0;
@@ -179,6 +184,8 @@ class EventThread : public android::EventThread {
 
     void onModeChanged(const scheduler::FrameRateMode&) override;
 
+    void onModeRejected(PhysicalDisplayId displayId, DisplayModeId modeId) override;
+
     void onFrameRateOverridesChanged(PhysicalDisplayId displayId,
                                      std::vector<FrameRateOverride> overrides) override;
 

services/surfaceflinger/Scheduler/Scheduler.cpp

@@ -465,6 +465,12 @@ bool Scheduler::onDisplayModeChanged(PhysicalDisplayId displayId, const FrameRat
 }
 #pragma clang diagnostic pop
 
+void Scheduler::onDisplayModeRejected(PhysicalDisplayId displayId, DisplayModeId modeId) {
+    if (hasEventThreads()) {
+        eventThreadFor(Cycle::Render).onModeRejected(displayId, modeId);
+    }
+}
+
 void Scheduler::emitModeChangeIfNeeded() {
     if (!mPolicy.modeOpt || !mPolicy.emittedModeOpt) {
         ALOGW("No mode change to emit");

services/surfaceflinger/Scheduler/Scheduler.h

@@ -36,12 +36,14 @@
 #include <ftl/non_null.h>
 #include <ftl/optional.h>
 #include <scheduler/Features.h>
+#include <scheduler/FrameRateMode.h>
 #include <scheduler/FrameTargeter.h>
 #include <scheduler/Time.h>
 #include <scheduler/VsyncConfig.h>
 #include <ui/DisplayId.h>
 #include <ui/DisplayMap.h>
 
+#include "DisplayHardware/DisplayMode.h"
 #include "EventThread.h"
 #include "FrameRateOverrideMappings.h"
 #include "ISchedulerCallback.h"
@@ -153,6 +155,8 @@ class Scheduler : public IEventThreadCallback, android::impl::MessageQueue {
     bool onDisplayModeChanged(PhysicalDisplayId, const FrameRateMode&,
                               bool clearContentRequirements) EXCLUDES(mPolicyLock);
 
+    void onDisplayModeRejected(PhysicalDisplayId, DisplayModeId);
+
     void enableSyntheticVsync(bool = true) REQUIRES(kMainThreadContext);
     void omitVsyncDispatching(bool) REQUIRES(kMainThreadContext);
 

services/surfaceflinger/SurfaceFlinger.cpp

@@ -1532,9 +1532,15 @@ void SurfaceFlinger::initiateDisplayModeChanges() {
         constraints.seamlessRequired = false;
         hal::VsyncPeriodChangeTimeline outTimeline;
 
-        if (mDisplayModeController.initiateModeChange(displayId, std::move(*desiredModeOpt),
-                                                      constraints, outTimeline) !=
-            display::DisplayModeController::ModeChangeResult::Changed) {
+        const auto error =
+                mDisplayModeController.initiateModeChange(displayId, std::move(*desiredModeOpt),
+                                                          constraints, outTimeline);
+        if (error != display::DisplayModeController::ModeChangeResult::Changed) {
+            dropModeRequest(displayId);
+            if (FlagManager::getInstance().display_config_error_hal() &&
+                error == display::DisplayModeController::ModeChangeResult::Rejected) {
+                mScheduler->onDisplayModeRejected(displayId, desiredModeId);
+            }
             continue;
         }