About resume time optimization for bus resume routine

[Peter Chen <peter.chen@xxxxxxxxxxxxx>]

Hi Alan,

When I try to optimize system resume time, I find bus resume routine
cost much time (> 20ms), even there is no device at any ports.
Let's take ehci bus resume as an example.

1. At ehci_bus_resume

	/* Some controller/firmware combinations need a delay during which
	 * they set up the port statuses.  See Bugzilla #8190. */
	spin_unlock_irq(&ehci->lock);
	msleep(8);
	spin_lock_irq(&ehci->lock);
Is it possible to add condition?

2. At hcd_bus_resume
	if (status == 0) {
		/* TRSMRCY = 10 msec */
		msleep(10);
This 10ms delay is needed when the device is connected and CONFIG_USB_SUSPEND
is not defined, can we add condition like:

	if (status == 0) {
	#ifndef CONFIG_USB_SUSPEND
		if (no_device_on_port)
			/* TRSMRCY = 10 msec */
			msleep(10);
	#endif
For the no_device_on_port, it needs to add flag at struct usb_hcd.

-- 

Best Regards,
Peter Chen

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