Android-vold源码分析之连接电脑OTG(11)

最新推荐文章于 2025-04-15 13:54:43 发布

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最新推荐文章于 2025-04-15 13:54:43 发布 · 1w 阅读

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#linux内核 #android #存储 #磁盘 #手机 #features

本文分析了Android系统中vold组件处理OTG（USB On-The-Go）连接电脑的实现。通过将磁盘设备写入标志文件并广播大容量存储连接状态来完成操作。涉及Linux内核、Android存储与磁盘管理。

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作者：gzshun. 原创作品，转载请标明出处！
来源：http://blog.youkuaiyun.com/gzshun

OTG是on-the-go的简称，是2001年由USB Implementers Forum公布，主要应用于各种不同的设备或移动设备间的联接，进行数据交换。特别是PDA、移动电话、消费类设备。改变如数码照相机、摄像机、打印机等设备间多种不同制式连接器，多达7种制式的存储卡间数据交换的不便。
对OTG介绍比较详细的在USB的官网，详细请见英文文档： http://www.usb.org/developers/onthego/。以下是官网的一个简要的介绍，贴出来看看：
USB On-The-Go and Embedded Host

Virtually every portable device now uses USB for PC connectivity. As these products increase in popularity, there is a growing need for them to communicate both with USB peripherals and directly with each other when a PC is not available. There is also an increase in the number of other, non-PC hosts (Embedded Hosts) which support USB in order to connect to USB peripherals.

The USB On-The-Go and Embedded Host Supplements addresses these scenarios by allowing portable devices and non-PC hosts to have the following enhancements:

Targeted host capability to communicate with selected other USB peripherals
Support for direct connections between OTG devices
Power saving features to preserve battery life
Revision 2.0 of the USB On-The-Go and Embed