Commit 90d28fb5 authored by Chunfeng Yun's avatar Chunfeng Yun Committed by Greg Kroah-Hartman
Browse files

usb: core: reduce power-on-good delay time of root hub 



Return the exactly delay time given by root hub descriptor,
this helps to reduce resume time etc.

Due to the root hub descriptor is usually provided by the host
controller driver, if there is compatibility for a root hub,
we can fix it easily without affect other root hub

Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarChunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1618017645-12259-1-git-send-email-chunfeng.yun@mediatek.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 26b75952

drivers/usb/core/hub.h

+4 −2
Original line number Diff line number Diff line
@@ -148,7 +148,9 @@ static inline unsigned hub_power_on_good_delay(struct usb_hub *hub) 
{

	unsigned delay = hub->descriptor->bPwrOn2PwrGood * 2;



	/* Wait at least 100 msec for power to become stable */

	if (!hub->hdev->parent)	/* root hub */

		return delay;

	else /* Wait at least 100 msec for power to become stable */

		return max(delay, 100U);

}