From: Alan Stern <stern@rowland.harvard.edu>
To: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: mathias.nyman@intel.com,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"open list:USB XHCI DRIVER" <linux-usb@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] xhci: Suspend ports to U3 directly from U1 or U2
Date: Wed, 10 Jun 2020 10:32:20 -0400 [thread overview]
Message-ID: <20200610143220.GC11727@rowland.harvard.edu> (raw)
In-Reply-To: <20200610064231.9454-1-kai.heng.feng@canonical.com>
On Wed, Jun 10, 2020 at 02:42:30PM +0800, Kai-Heng Feng wrote:
> xHCI spec "4.15.1 Port Suspend" states that port can be put to U3 as long
> as Enabled bit is set and from U0, U1 or U2 state.
>
> Currently only USB_PORT_FEAT_LINK_STATE puts port to U3 directly, let's
> do the same for USB_PORT_FEAT_SUSPEND and bus suspend case.
>
> This is particularly useful for USB2 devices, which may take a very long
> time to switch USB2 LPM on and off.
Have these two patches been tested with a variety of USB-2.0 and USB-2.1
devices?
Alan Stern
next prev parent reply other threads:[~2020-06-10 14:32 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-10 6:42 [PATCH 1/2] xhci: Suspend ports to U3 directly from U1 or U2 Kai-Heng Feng
2020-06-10 6:42 ` [PATCH 2/2] USB: hub: Suspend and resume port with LPM enabled Kai-Heng Feng
2020-06-10 9:21 ` Sergei Shtylyov
2020-06-10 14:32 ` Alan Stern [this message]
2020-06-10 15:43 ` [PATCH 1/2] xhci: Suspend ports to U3 directly from U1 or U2 Kai-Heng Feng
2020-06-10 15:58 ` Mathias Nyman
2020-06-11 7:41 ` Kai-Heng Feng
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