USB Remote wakeup

According to USB 2.0, section 7.1.7.7 Resume:

A device with remote wakeup capability may not generate resume signaling unless the bus has been continuously in the Idle state for 5 ms (TWTRSM). This allows the hubs to get into their Suspend state and prepare for propagating resume signaling. The remote wakeup device must hold the resume signaling for at least 1 ms but for no more than 15 ms (TDRSMUP). At the end of this period, the device stops driving the bus (puts its drivers into the high-impedance state and does not drive the bus to the J state).

So, multiple resume signaling is not allowed.

The resume 'K' signaling from the device may interfere with data coming from the hubs/host, and lead to errors.

Hi, I have a query on USB remote wakeup. While the device performs resume signalling for ~1-15msec which wakes up the hub and inturn the host.

What if there are multiple resume signalling's initiated from the device when the hub/host is already up ?

Will those consecutive resume signalling be ignored from host ?

Kindly let me know your valuable inputs.

Regards, Sandeep

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