From d934151ef36808b1cf926b9bc123092e1e2c3b71 Mon Sep 17 00:00:00 2001
From: daniml3 <daniel@danielml.dev>
Date: Sun, 22 Aug 2021 16:34:00 +0200
Subject: [PATCH] sweet: override the SetRefreshRate HWC builtin display
 function

* This function causes the refresh rate to change randomly, and
  produces flickering on the display

* Override the original function by renaming the symbol so linker
  uses the symbol from the shim instead of the original library's
  symbol

Signed-off-by: daniml3 <daniel@danielml.dev>
Change-Id: I2fa6b3f834df79c32d22f5a057da2108cc9cacab
---
 device.mk                   |  3 +++
 display/Android.bp          |  8 ++++++++
 display/Android.mk          | 24 ++++++++++++++++++++++++
 display/display_builtin.cpp |  3 +++
 4 files changed, 38 insertions(+)
 create mode 100644 display/Android.bp
 create mode 100644 display/Android.mk
 create mode 100644 display/display_builtin.cpp

diff --git a/device.mk b/device.mk
index 28e0fe9..2f6b5f7 100644
--- a/device.mk
+++ b/device.mk
@@ -39,6 +39,9 @@ PRODUCT_PACKAGES += \
 PRODUCT_COPY_FILES += \
     $(LOCAL_PATH)/configs/display/qdcm_calib_data_xiaomi_k6_38_0c_0a_fhd_dsc_video_dsi_panel.xml:$(TARGET_COPY_OUT_VENDOR)/etc/qdcm_calib_data_xiaomi_k6_38_0c_0a_fhd_dsc_video_dsi_panel.xml
 
+PRODUCT_PACKAGES += \
+    libsdmcore-shim
+
 # Fstab
 PRODUCT_COPY_FILES += \
     $(LOCAL_PATH)/rootdir/etc/fstab.qcom:$(TARGET_COPY_OUT_RAMDISK)/fstab.qcom \
diff --git a/display/Android.bp b/display/Android.bp
new file mode 100644
index 0000000..4362db8
--- /dev/null
+++ b/display/Android.bp
@@ -0,0 +1,8 @@
+cc_library_shared {
+    name: "libsdmcore-shim",
+    srcs: [
+        "display_builtin.cpp"
+    ],
+    required: ["libsdmcore-patch"],
+    vendor: true,
+}
diff --git a/display/Android.mk b/display/Android.mk
new file mode 100644
index 0000000..34f67dd
--- /dev/null
+++ b/display/Android.mk
@@ -0,0 +1,24 @@
+LOCAL_PATH := $(call my-dir)
+
+HWC := hwcomposer.$(TARGET_BOARD_PLATFORM)
+LIBSDMCORE := $(TARGET_OUT_VENDOR)/lib64/libsdmcore.so
+HWCOMPOSER := $(TARGET_OUT_VENDOR)/lib64/hw/$(HWC).so
+
+ORIGINAL_SYMBOL := _ZN3sdm14DisplayBuiltIn14SetRefreshRateEjb
+CUSTOM_SYMBOL := _ZN3sdm14DisplayBuiltIn14SetRefreshCustEjb
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := libsdmcore-patch
+LOCAL_PREBUILT_MODULE_FILE := /dev/null
+LOCAL_MODULE_CLASS := ETC
+LOCAL_VENDOR_MODULE := true
+LOCAL_REQUIRED_MODULES := $(HWC) libsdmcore
+
+LOCAL_POST_INSTALL_CMD := \
+    cp $(PRODUCT_OUT)/symbols/vendor/lib64/libsdmcore.so $(LIBSDMCORE) && \
+    cp $(PRODUCT_OUT)/symbols/vendor/lib64/hw/$(HWC).so $(HWCOMPOSER) && \
+    sed -i s/$(ORIGINAL_SYMBOL)/$(CUSTOM_SYMBOL)/g $(LIBSDMCORE) && \
+    sed -i s/libdisplaydebug/libsdmcore-shim/g $(HWCOMPOSER) && \
+    rm $(TARGET_OUT_VENDOR)/etc/$(LOCAL_MODULE)
+
+include $(BUILD_PREBUILT)
diff --git a/display/display_builtin.cpp b/display/display_builtin.cpp
new file mode 100644
index 0000000..9588293
--- /dev/null
+++ b/display/display_builtin.cpp
@@ -0,0 +1,3 @@
+#include <stdint.h>
+
+extern "C" void _ZN3sdm14DisplayBuiltIn14SetRefreshCustEjb(uint32_t, bool) {}