From: Chunfeng Yun <chunfeng.yun@mediatek.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Alan Stern <stern@rowland.harvard.edu>
Cc: Matthias Brugger <matthias.bgg@gmail.com>,
Chunfeng Yun <chunfeng.yun@mediatek.com>,
Nishad Kamdar <nishadkamdar@gmail.com>,
<linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-mediatek@lists.infradead.org>,
Eddie Hung <eddie.hung@mediatek.com>
Subject: [PATCH v2] usb: core: reduce power-on-good delay time of root hub
Date: Sat, 10 Apr 2021 09:20:45 +0800 [thread overview]
Message-ID: <1618017645-12259-1-git-send-email-chunfeng.yun@mediatek.com> (raw)
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 <stern@rowland.harvard.edu>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
---
v2: remove RFC tag, and add acked-by Alan
---
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,
--
2.18.0
next reply other threads:[~2021-04-10 1:21 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-10 1:20 Chunfeng Yun [this message]
2021-11-01 3:33 ` Walt Jr. Brake
[not found] ` <5e907ccd-40bb-2ece-fe05-1a65a74f3aa2@gmail.com>
2021-11-01 14:06 ` Alan Stern
2021-11-02 9:05 ` Mathias Nyman
2021-11-02 20:29 ` Walt Jr. Brake
2021-11-03 20:37 ` Mathias Nyman
2021-11-05 10:00 ` Greg Kroah-Hartman
2021-11-05 13:30 ` Alan Stern
2021-11-05 16:00 ` [PATCH] xhci: Fix USB 3.1 enumeration issues by increasing roothub power-on-good delay Mathias Nyman
2021-11-05 16:09 ` Mathias Nyman
2021-11-05 17:32 ` Walt Jr. Brake
2021-11-05 19:41 ` Mathias Nyman
2021-11-05 16:15 ` Greg KH
2021-11-05 19:56 ` Mathias Nyman
2021-11-06 14:41 ` Greg KH
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