Banana Pi M64 Android修改分辨率为480x1280横屏显示
由于项目需要，使用了一块480x1280分辨率的屏，但是M64官方Android系统只提供720p和1280p分辨率的选择，无法正常驱动这块屏。经过长期摸索，终于搞清楚了要修改的文件：
一、修改内核文件
1.lichee/linux-3.10/drivers/video/sunxi/disp2/hdmi/hdmi_core.c
修改自己屏幕的时序。
2.修改Android的hardware文件：
android/hardware/aw/hwc/tulip/hwc_uevent.cpp
android/hardware/aw/hwc/octopus/hwc_uevent.cpp
android/hardware/aw/hwc/astar/hal.cpp
android/hardware/aw/hwc/kylin/hal.cpp
修改
DISP_TV_MOD_720P_60HZ和
DISP_TV_MOD_720P_50HZ分辨率为480x1280（原为1280x720）
二、修改布局
由于需要横屏显示，所以还需要修改布局，以支持横屏
（一）支持横屏显示选项ro.sf.hwrotation
1.android/frameworks/native/services/surfaceflinger/DisplayDevice.h，
添加变量
// Current active config
int mActiveConfig;
//修改：支持横屏
// Panel hardware rotation
int32_t mHardwareRotation;
去掉 status_t orientationToTransfrom(int orientation, int w, int h, Transform* tr);的
Static 声明
2.android/frameworks/native/services/surfaceflinger/DisplayDevice.cpp
DisplayDevice::DisplayDevice函数添加：
property_get("ro.panel.mountflip", property, "0”);
mPanelMountFlip = atoi(property);
// initialize the display orientation transform.
DisplayDevice::orientationToTransfrom函数添加：
//修改：支持橫屏
if (mHardwareRotation && mType == DISPLAY_PRIMARY) {
orientation += mHardwareRotation;
orientation %= 4;
}
switch (orientation) {
…
DisplayDevice::setProjection函数添加：
if (!frame.isValid()) {
// the destination frame can be invalid if it has never been set,
// in that case we assume the whole display frame.
//修改：支持橫屏
if (mHardwareRotation == 1 || mHardwareRotation == 3) {
frame = Rect(h, w);
} else {
frame = Rect(w, h);
}
//frame = Rect(w, h);
}
3.android/frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
SurfaceFlinger::getDisplayConfigs函数添加：
//修改：支持橫屏
char value[PROPERTY_VALUE_MAX];
property_get("ro.sf.hwrotation", value, "0");
int additionalRot = atoi(value) / 90;
if ((type == DisplayDevice::DISPLAY_PRIMARY) && (additionalRot & DisplayState::eOrientationSwapMask)) {
info.h = hwConfig.width;
info.w = hwConfig.height;
info.xdpi = ydpi;
info.ydpi = xdpi;
}
else {
info.w = hwConfig.width;
info.h = hwConfig.height;
info.xdpi = xdpi;
info.ydpi = ydpi;
}
/*
info.w = hwConfig.width;
info.h = hwConfig.height;
info.xdpi = xdpi;
info.ydpi = ydpi;
*/
info.fps = float(1e9 / hwConfig.refresh);
info.appVsyncOffset = VSYNC_EVENT_PHASE_OFFSET_NS;
info.colorTransform = hwConfig.colorTransform;
经过以上修改后，重新编译内核和源码，终于可以正常横屏显示了，希望能帮到有同样问题的朋友。