SF: Defer setDisplayBrightness to Binder thread

setDisplayBrightness blocks for a long time so cannot run on the main
thread. Keep display lookup on the main thread, but return a deferred
future to the Binder thread and run it there.

Bug: 154202427
Bug: 123715322
Test: systrace with backdoor to set brightness
Change-Id: I88e60c95db5fdcaa1bf5ebb9711e3bf5ab6539a1

7 files changed, 46 insertions, 33 deletions

diff --git a/services/surfaceflinger/CompositionEngine/tests/MockHWComposer.h b/services/surfaceflinger/CompositionEngine/tests/MockHWComposer.h
index 27266b76f6..75a4fec8fb 100644
--- a/services/surfaceflinger/CompositionEngine/tests/MockHWComposer.h
+++ b/services/surfaceflinger/CompositionEngine/tests/MockHWComposer.h
@@ -74,7 +74,7 @@ public:
     MOCK_METHOD4(setDisplayContentSamplingEnabled, status_t(DisplayId, bool, uint8_t, uint64_t));
     MOCK_METHOD4(getDisplayedContentSample,
                  status_t(DisplayId, uint64_t, uint64_t, DisplayedFrameStats*));
-    MOCK_METHOD2(setDisplayBrightness, status_t(DisplayId, float));
+    MOCK_METHOD2(setDisplayBrightness, std::future<status_t>(DisplayId, float));
     MOCK_METHOD2(getDisplayBrightnessSupport, status_t(DisplayId, bool*));
 
     MOCK_METHOD2(onHotplug,
diff --git a/services/surfaceflinger/DisplayHardware/HWC2.cpp b/services/surfaceflinger/DisplayHardware/HWC2.cpp
index d6dbd573d7..0ea33408db 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWC2.cpp
@@ -25,7 +25,6 @@
 #define ATRACE_TAG ATRACE_TAG_GRAPHICS
 
 #include "HWC2.h"
-#include "ComposerHal.h"
 
 #include <ui/Fence.h>
 #include <ui/FloatRect.h>
@@ -38,6 +37,9 @@
 #include <iterator>
 #include <set>
 
+#include "../Promise.h"
+#include "ComposerHal.h"
+
 namespace android {
 
 using android::Fence;
@@ -640,12 +642,14 @@ Error Display::presentOrValidate(uint32_t* outNumTypes, uint32_t* outNumRequests
     return error;
 }
 
-Error Display::setDisplayBrightness(float brightness) const {
-    const auto intError = mComposer.setDisplayBrightness(mId, brightness);
-    return static_cast<Error>(intError);
+std::future<Error> Display::setDisplayBrightness(float brightness) {
+    return promise::defer([composer = &mComposer, id = mId, brightness] {
+        const auto intError = composer->setDisplayBrightness(id, brightness);
+        return static_cast<Error>(intError);
+    });
 }
 
-Error Display::setAutoLowLatencyMode(bool on) const {
+Error Display::setAutoLowLatencyMode(bool on) {
     auto intError = mComposer.setAutoLowLatencyMode(mId, on);
     return static_cast<Error>(intError);
 }
@@ -659,7 +663,7 @@ Error Display::getSupportedContentTypes(std::vector<ContentType>* outSupportedCo
     return static_cast<Error>(intError);
 }
 
-Error Display::setContentType(ContentType contentType) const {
+Error Display::setContentType(ContentType contentType) {
     auto intError = mComposer.setContentType(mId, contentType);
     return static_cast<Error>(intError);
 }
diff --git a/services/surfaceflinger/DisplayHardware/HWC2.h b/services/surfaceflinger/DisplayHardware/HWC2.h
index af31df8216..f4c7fddea9 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2.h
+++ b/services/surfaceflinger/DisplayHardware/HWC2.h
@@ -27,6 +27,7 @@
 #include <utils/Timers.h>
 
 #include <functional>
+#include <future>
 #include <string>
 #include <unordered_map>
 #include <unordered_set>
@@ -221,18 +222,18 @@ public:
     [[clang::warn_unused_result]] virtual hal::Error presentOrValidate(
             uint32_t* outNumTypes, uint32_t* outNumRequests,
             android::sp<android::Fence>* outPresentFence, uint32_t* state) = 0;
-    [[clang::warn_unused_result]] virtual hal::Error setDisplayBrightness(
-            float brightness) const = 0;
+    [[clang::warn_unused_result]] virtual std::future<hal::Error> setDisplayBrightness(
+            float brightness) = 0;
     [[clang::warn_unused_result]] virtual hal::Error getDisplayVsyncPeriod(
             nsecs_t* outVsyncPeriod) const = 0;
     [[clang::warn_unused_result]] virtual hal::Error setActiveConfigWithConstraints(
             const std::shared_ptr<const HWC2::Display::Config>& config,
             const hal::VsyncPeriodChangeConstraints& constraints,
             hal::VsyncPeriodChangeTimeline* outTimeline) = 0;
-    [[clang::warn_unused_result]] virtual hal::Error setAutoLowLatencyMode(bool on) const = 0;
+    [[clang::warn_unused_result]] virtual hal::Error setAutoLowLatencyMode(bool on) = 0;
     [[clang::warn_unused_result]] virtual hal::Error getSupportedContentTypes(
             std::vector<hal::ContentType>*) const = 0;
-    [[clang::warn_unused_result]] virtual hal::Error setContentType(hal::ContentType) const = 0;
+    [[clang::warn_unused_result]] virtual hal::Error setContentType(hal::ContentType) = 0;
 };
 
 namespace impl {
@@ -294,16 +295,16 @@ public:
     hal::Error presentOrValidate(uint32_t* outNumTypes, uint32_t* outNumRequests,
                                  android::sp<android::Fence>* outPresentFence,
                                  uint32_t* state) override;
-    hal::Error setDisplayBrightness(float brightness) const override;
+    std::future<hal::Error> setDisplayBrightness(float brightness) override;
     hal::Error getDisplayVsyncPeriod(nsecs_t* outVsyncPeriod) const override;
     hal::Error setActiveConfigWithConstraints(
             const std::shared_ptr<const HWC2::Display::Config>& config,
             const hal::VsyncPeriodChangeConstraints& constraints,
             hal::VsyncPeriodChangeTimeline* outTimeline) override;
-    hal::Error setAutoLowLatencyMode(bool on) const override;
+    hal::Error setAutoLowLatencyMode(bool on) override;
     hal::Error getSupportedContentTypes(
             std::vector<hal::ContentType>* outSupportedContentTypes) const override;
-    hal::Error setContentType(hal::ContentType contentType) const override;
+    hal::Error setContentType(hal::ContentType) override;
     // Other Display methods
     hal::HWDisplayId getId() const override { return mId; }
     bool isConnected() const override { return mIsConnected; }
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.cpp b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
index 4344a8deec..038cec4aa5 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
@@ -36,6 +36,7 @@
 #include <utils/Trace.h>
 
 #include "../Layer.h" // needed only for debugging
+#include "../Promise.h"
 #include "../SurfaceFlinger.h"
 #include "ComposerHal.h"
 #include "HWC2.h"
@@ -794,17 +795,21 @@ status_t HWComposer::getDisplayedContentSample(DisplayId displayId, uint64_t max
     return NO_ERROR;
 }
 
-status_t HWComposer::setDisplayBrightness(DisplayId displayId, float brightness) {
-    RETURN_IF_INVALID_DISPLAY(displayId, BAD_INDEX);
-    const auto error = mDisplayData[displayId].hwcDisplay->setDisplayBrightness(brightness);
-    if (error == hal::Error::UNSUPPORTED) {
-        RETURN_IF_HWC_ERROR(error, displayId, INVALID_OPERATION);
-    }
-    if (error == hal::Error::BAD_PARAMETER) {
-        RETURN_IF_HWC_ERROR(error, displayId, BAD_VALUE);
-    }
-    RETURN_IF_HWC_ERROR(error, displayId, UNKNOWN_ERROR);
-    return NO_ERROR;
+std::future<status_t> HWComposer::setDisplayBrightness(DisplayId displayId, float brightness) {
+    RETURN_IF_INVALID_DISPLAY(displayId, promise::yield<status_t>(BAD_INDEX));
+    auto& display = mDisplayData[displayId].hwcDisplay;
+
+    return promise::chain(display->setDisplayBrightness(brightness))
+            .then([displayId](hal::Error error) -> status_t {
+                if (error == hal::Error::UNSUPPORTED) {
+                    RETURN_IF_HWC_ERROR(error, displayId, INVALID_OPERATION);
+                }
+                if (error == hal::Error::BAD_PARAMETER) {
+                    RETURN_IF_HWC_ERROR(error, displayId, BAD_VALUE);
+                }
+                RETURN_IF_HWC_ERROR(error, displayId, UNKNOWN_ERROR);
+                return NO_ERROR;
+            });
 }
 
 bool HWComposer::isUsingVrComposer() const {
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.h b/services/surfaceflinger/DisplayHardware/HWComposer.h
index cfa21932e9..b7e9f3a693 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.h
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.h
@@ -18,6 +18,7 @@
 #define ANDROID_SF_HWCOMPOSER_H
 
 #include <cstdint>
+#include <future>
 #include <memory>
 #include <mutex>
 #include <optional>
@@ -163,7 +164,7 @@ public:
                                                DisplayedFrameStats* outStats) = 0;
 
     // Sets the brightness of a display.
-    virtual status_t setDisplayBrightness(DisplayId displayId, float brightness) = 0;
+    virtual std::future<status_t> setDisplayBrightness(DisplayId displayId, float brightness) = 0;
 
     // Events handling ---------------------------------------------------------
 
@@ -305,7 +306,7 @@ public:
                                               uint8_t componentMask, uint64_t maxFrames) override;
     status_t getDisplayedContentSample(DisplayId displayId, uint64_t maxFrames, uint64_t timestamp,
                                        DisplayedFrameStats* outStats) override;
-    status_t setDisplayBrightness(DisplayId displayId, float brightness) override;
+    std::future<status_t> setDisplayBrightness(DisplayId displayId, float brightness) override;
 
     // Events handling ---------------------------------------------------------
 
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 29434990f6..794e8a7a44 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -108,6 +108,7 @@
 #include "LayerVector.h"
 #include "MonitoredProducer.h"
 #include "NativeWindowSurface.h"
+#include "Promise.h"
 #include "RefreshRateOverlay.h"
 #include "RegionSamplingThread.h"
 #include "Scheduler/DispSync.h"
@@ -1491,14 +1492,15 @@ status_t SurfaceFlinger::setDisplayBrightness(const sp<IBinder>& displayToken, f
         return BAD_VALUE;
     }
 
-    return schedule([=]() -> status_t {
+    return promise::chain(schedule([=] {
                if (const auto displayId = getPhysicalDisplayIdLocked(displayToken)) {
                    return getHwComposer().setDisplayBrightness(*displayId, brightness);
                } else {
                    ALOGE("%s: Invalid display token %p", __FUNCTION__, displayToken.get());
-                   return NAME_NOT_FOUND;
+                   return promise::yield<status_t>(NAME_NOT_FOUND);
                }
-           })
+           }))
+            .then([](std::future<status_t> task) { return task; })
             .get();
 }
 
diff --git a/services/surfaceflinger/tests/unittests/mock/DisplayHardware/MockDisplay.h b/services/surfaceflinger/tests/unittests/mock/DisplayHardware/MockDisplay.h
index 67d3e1cd2f..dade9fc1e0 100644
--- a/services/surfaceflinger/tests/unittests/mock/DisplayHardware/MockDisplay.h
+++ b/services/surfaceflinger/tests/unittests/mock/DisplayHardware/MockDisplay.h
@@ -84,15 +84,15 @@ public:
     MOCK_METHOD2(validate, hal::Error(uint32_t*, uint32_t*));
     MOCK_METHOD4(presentOrValidate,
                  hal::Error(uint32_t*, uint32_t*, android::sp<android::Fence>*, uint32_t*));
-    MOCK_CONST_METHOD1(setDisplayBrightness, hal::Error(float));
+    MOCK_METHOD1(setDisplayBrightness, std::future<hal::Error>(float));
     MOCK_CONST_METHOD1(getDisplayVsyncPeriod, hal::Error(nsecs_t*));
     MOCK_METHOD3(setActiveConfigWithConstraints,
                  hal::Error(const std::shared_ptr<const HWC2::Display::Config>&,
                             const hal::VsyncPeriodChangeConstraints&,
                             hal::VsyncPeriodChangeTimeline*));
-    MOCK_CONST_METHOD1(setAutoLowLatencyMode, hal::Error(bool on));
+    MOCK_METHOD1(setAutoLowLatencyMode, hal::Error(bool on));
     MOCK_CONST_METHOD1(getSupportedContentTypes, hal::Error(std::vector<hal::ContentType>*));
-    MOCK_CONST_METHOD1(setContentType, hal::Error(hal::ContentType));
+    MOCK_METHOD1(setContentType, hal::Error(hal::ContentType));
     MOCK_CONST_METHOD1(getConnectionType, hal::Error(android::DisplayConnectionType*));
     MOCK_CONST_METHOD0(isVsyncPeriodSwitchSupported, bool());
 };