A133 Android10 USB Camera插拔过程出现概率性无法打开问题

操作：插拔USB摄像头，打开Camera应用；

---

现象一：

从日志上看，存在插入USB Camera后会快速的被remove掉，当前的status为0；

1. 问题分析

通过在onDeviceStatusChanged中添加CallStack,发现会进来两次，一次是hal层provider remove,另外一次是cameraserver检测到USB DETACH然后就走了移除事件；

2. 解决办法

避免两次remove的动作出现，由于cameraserver remove的动作是谷歌针对Lazy hal加入的，USB Camera我们不申明为lazy,如果是单USB Camera方案（无CSI Camera），可以按照如下进行修改:

diff --git a/android/device/softwinner/ceres-b6/ceres_b6.mk b/android/device/softwinner/ceres-b6/ceres_b6.mk
index 1c86ad6b6f..10a44d41c7 100644
--- a/android/device/softwinner/ceres-b6/ceres_b6.mk
+++ b/android/device/softwinner/ceres-b6/ceres_b6.mk
@@ -99,7 +99,7 @@ ifeq ($(CONFIG_LOW_RAM_DEVICE),true)
         dalvik.vm.madvise-random=true
 
     # camera hal: Q Regular version must use camera hal v3
-    USE_CAMERA_HAL_3_4 := true
+    USE_CAMERA_HAL_3_4 := false
 
 else # ifeq ($(CONFIG_LOW_RAM_DEVICE),true)
     $(call inherit-product, build/target/product/full_base.mk)
@@ -264,8 +264,10 @@ PRODUCT_SYSTEM_DEFAULT_PROPERTIES += \
     ro.minui.default_rotation=ROTATION_LEFT \
     ro.recovery.ui.touch_high_threshold=60
 
+ifeq ($(USE_CAMERA_HAL_3_4),true)
 PRODUCT_PROPERTY_OVERRIDES += \
     ro.camera.enableLazyHal=true
+endif

---

现象二：

日志打印：
logcat --pid=$(pidof [email protected])
提示open dev/video节点的时候No such device。

1. 问题分析

摄像头刚连接上不稳定，所以open的时候上报节点不存在；

2. 解决办法

增加retry机制保证稳定后open成功

diff --git a/android/hardware/interfaces/camera/provider/2.4/default/ExternalCameraProviderImpl_2_4.cpp b/android/hardware/interfaces/camera/provider/2.4/default/ExternalCameraProviderImpl_2_4.cpp
index 3ae47f23ce..432abd414e 100644
--- a/android/hardware/interfaces/camera/provider/2.4/default/ExternalCameraProviderImpl_2_4.cpp
+++ b/android/hardware/interfaces/camera/provider/2.4/default/ExternalCameraProviderImpl_2_4.cpp
@@ -237,8 +237,17 @@ void ExternalCameraProviderImpl_2_4::addExternalCamera(const char* devName) {
    
    
 void ExternalCameraProviderImpl_2_4::deviceAdded(const char* devName) {
    
    
     {
    
    
         base::unique_fd fd(::open(devName, O_RDWR));
-        if (fd.get() < 0) {
    
    
-            ALOGE("%s open v4l2 device %s failed:%s", __FUNCTION__, devName, strerror(errno));
+       for (int i=0; i<20; i++) {
    
    
+          if (fd.get() < 0 ) {
    
    
+               ALOGE("%s open v4l2 device %s failed:%s %d time", __FUNCTION__, devName, strerror(errno), i);
+               fd.reset(::open(devName, O_RDWR));
+               std::this_thread::sleep_for (std::chrono::milliseconds(50));
+           } else {
    
    
+               break;
+           }
+       }
+       if (fd.get() < 0) {
    
    
+            ALOGE("%s open v4l2 device %s finally failed:%s", __FUNCTION__, devName, strerror(errno));
             return;
         }