HWComposer: setPowerMode to DOZE even if support is unknown

If a display has not been turned on since boot, we do not know whether
it supports doze. Rather than treating this as not supported, make
Display::supportsDoze return an error if the capabilities have not been
queried yet. If supportsDoze returns this error, try to set the mode to
DOZE(_SUSPEND) anyway. This allows properly waking from AOD.

If the call to Display::setPowerMode fails, this means it truly is not
supported, so fallback to the old behavior of turning it ON.

Fixes: 274722476
Test: manual
Test: GraphicsComposerAidlTest#SetPowerModeUnsupported
Change-Id: Ia88603565713ea4b6ec5142b693d2df1302131ea

2 files changed, 24 insertions, 6 deletions

diff --git a/services/surfaceflinger/DisplayHardware/HWC2.cpp b/services/surfaceflinger/DisplayHardware/HWC2.cpp
index aaf2523338..0c2b77de7d 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWC2.cpp
@@ -311,6 +311,14 @@ bool Display::hasCapability(DisplayCapability capability) const {
 }
 
 Error Display::supportsDoze(bool* outSupport) const {
+    {
+        std::scoped_lock lock(mDisplayCapabilitiesMutex);
+        if (!mDisplayCapabilities) {
+            // The display has not turned on since boot, so DOZE support is unknown.
+            ALOGW("%s: haven't queried capabilities yet!", __func__);
+            return Error::NO_RESOURCES;
+        }
+    }
     *outSupport = hasCapability(DisplayCapability::DOZE);
     return Error::NONE;
 }
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.cpp b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
index 3177b33538..a9bb928f59 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
@@ -616,19 +616,29 @@ status_t HWComposer::setPowerMode(PhysicalDisplayId displayId, hal::PowerMode mo
             ALOGV("setPowerMode: Calling HWC %s", to_string(mode).c_str());
             {
                 bool supportsDoze = false;
-                auto error = hwcDisplay->supportsDoze(&supportsDoze);
-                if (error != hal::Error::NONE) {
-                    LOG_HWC_ERROR("supportsDoze", error, displayId);
-                }
+                const auto queryDozeError = hwcDisplay->supportsDoze(&supportsDoze);
 
-                if (!supportsDoze) {
+                // queryDozeError might be NO_RESOURCES, in the case of a display that has never
+                // been turned on. In that case, attempt to set to DOZE anyway.
+                if (!supportsDoze && queryDozeError == hal::Error::NONE) {
                     mode = hal::PowerMode::ON;
                 }
 
-                error = hwcDisplay->setPowerMode(mode);
+                auto error = hwcDisplay->setPowerMode(mode);
                 if (error != hal::Error::NONE) {
                     LOG_HWC_ERROR(("setPowerMode(" + to_string(mode) + ")").c_str(), error,
                                   displayId);
+                    // If the display had never been turned on, so its doze
+                    // support was unknown, it may truly not support doze. Try
+                    // switching it to ON instead.
+                    if (queryDozeError == hal::Error::NO_RESOURCES) {
+                        ALOGD("%s: failed to set %s to %s. Trying again with ON", __func__,
+                              to_string(displayId).c_str(), to_string(mode).c_str());
+                        error = hwcDisplay->setPowerMode(hal::PowerMode::ON);
+                        if (error != hal::Error::NONE) {
+                            LOG_HWC_ERROR("setPowerMode(ON)", error, displayId);
+                        }
+                    }
                 }
             }
             break;