Appendix A: Standard Device Requests

Set/Clear Feature

The “Set” and “Clear Feature” requests provide a method of enabling and disabling a set of features defined by the feature selector value. Two features are defined for the standard device requests as shown inTable A-3.

Table A-3: Feature Selectors

Device Remote Wakeup

Some devices may be designed to wake the system in the event of a global suspend or to wake a hub port that has been selectively suspended. (See Chapter 9 for details regarding suspend.) The “Set Feature” request, with device remote wakeup selected, enables a device to signal wakeup to the hub. The “Clear Device Remote Wakeup” request prevents a device from signaling remote wakeup to the hub. Whether a device’s ability to signal remote wakeup is currently enabled or disabled is reported to software via the “Get Status” request.

Endpoint Stall

Software has the ability to stall a given endpoint or to clear a stall condition. The “Set” and “Clear Endpoint Stall” requests define which endpoint within the device is being targeted via the “index” field of the setup transaction. A stall bit is defined for each endpoint that indicates whether the endpoint is currently stalled or not. The stall bit is read in conjunction with the “Get Status” request.

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