"bInterval" value for High Speed BULK out endpoint

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Hello All,

According to the USB 2.0 spec, "bInterval" value for the High Speed Bulk OUT endpoint must specify the maximum NAK rate of the endpoint. (pg. 271). But on page 273 of the specs, its written "For high-speed bulk and control OUT endpoints, the bInterval field is only used for compliance purposes; the host controller is not required to change its behavior based on the value in this field."

I wanted to know, for High speed Bulk OUT endpoints, what should be the value of bInterval. If it is set to 0, it indicates that the endpoint never NAKs. So, does this mean that device can never NAK?

Consider the following case:
The host is sending data, device sends an ACK for first chunk;
The host will send the next chunk; if for some reason, the device is not able to receive data, will the host retry if bInterval = 0?

I am asking this by considering the USB android gadget composite driver, gadget/f_mass_storage.c where the bInterval is set to 1 for high speed bulk out endpoint for mass storage interface.

Thanks for your time.

Regards,
Mohan
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