From 90d28fb53d4a51299ff324dede015d5cb11b88a2 Mon Sep 17 00:00:00 2001 From: Chunfeng Yun Date: Sat, 10 Apr 2021 09:20:45 +0800 Subject: [PATCH] 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: Alan Stern Signed-off-by: Chunfeng Yun Link: https://lore.kernel.org/r/1618017645-12259-1-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hub.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h index 73f4482d833a..22ea1f4f2d66 100644 --- a/drivers/usb/core/hub.h +++ b/drivers/usb/core/hub.h @@ -148,8 +148,10 @@ 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 */ - return max(delay, 100U); + if (!hub->hdev->parent) /* root hub */ + return delay; + else /* Wait at least 100 msec for power to become stable */ + return max(delay, 100U); } static inline int hub_port_debounce_be_connected(struct usb_hub *hub, -- 2.11.0