On Sun, 06 Dec 2009 23:32:16 -0600, Sandeeptssmg wrote:
> 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 ?
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.
Reply by Sandeeptssmg●December 7, 20092009-12-07
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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